Updated the Code of Conduct (#2365)

This updates the Code of Conduct to the Contributor Covenant v2.1 version (we were using the 2.0 version until now). Changes are very minor. As far as I can tell, the only content difference is the explicit mention of _caste_ and _color_ among the potential traits that could cause harassment.

Then it just changes the format a bit to make links a bit more user friendly, by not posting URLs directly.

But I have a question: should we update the contact method? It currently says the following:

> Instances of abusive, harassing, or otherwise unacceptable behavior may be reported to the community leaders responsible for enforcement at [discord](https://discord.gg/tUFFk9Y) by contacting _JaseW_.

Maybe we should mention the `@boa-dev` group, and that they can contact anyone there. What do you think? I would also like to update this before https://github.com/boa-dev/ryu-js/pull/22

CODE_OF_CONDUCT.md

@@ -6,8 +6,8 @@ We as members, contributors, and leaders pledge to make participation in our
 community a harassment-free experience for everyone, regardless of age, body
 size, visible or invisible disability, ethnicity, sex characteristics, gender
 identity and expression, level of experience, education, socio-economic status,
-nationality, personal appearance, race, religion, or sexual identity
-and orientation.
+nationality, personal appearance, race, caste, color, religion, or sexual
+identity and orientation.
 
 We pledge to act and interact in ways that contribute to an open, welcoming,
 diverse, inclusive, and healthy community.
@@ -22,17 +22,17 @@ community include:
 - Giving and gracefully accepting constructive feedback
 - Accepting responsibility and apologizing to those affected by our mistakes,
   and learning from the experience
-- Focusing on what is best not just for us as individuals, but for the
-  overall community
+- Focusing on what is best not just for us as individuals, but for the overall
+  community
 
 Examples of unacceptable behavior include:
 
-- The use of sexualized language or imagery, and sexual attention or
-  advances of any kind
+- The use of sexualized language or imagery, and sexual attention or advances of
+  any kind
 - Trolling, insulting or derogatory comments, and personal or political attacks
 - Public or private harassment
-- Publishing others' private information, such as a physical or email
-  address, without their explicit permission
+- Publishing others' private information, such as a physical or email address,
+  without their explicit permission
 - Other conduct which could reasonably be considered inappropriate in a
   professional setting
 
@@ -60,7 +60,8 @@ representative at an online or offline event.
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
 reported to the community leaders responsible for enforcement at
-[discord](https://discord.gg/tUFFk9Y) by contacting _JaseW_.
+[discord](https://discord.gg/tUFFk9Y) by contacting anyone in the _@boa_dev_
+group (check the yellow usernames).
 All complaints will be reviewed and investigated promptly and fairly.
 
 All community leaders are obligated to respect the privacy and security of the
@@ -82,15 +83,15 @@ behavior was inappropriate. A public apology may be requested.
 
 ### 2. Warning
 
-**Community Impact**: A violation through a single incident or series
-of actions.
+**Community Impact**: A violation through a single incident or series of
+actions.
 
 **Consequence**: A warning with consequences for continued behavior. No
 interaction with the people involved, including unsolicited interaction with
 those enforcing the Code of Conduct, for a specified period of time. This
 includes avoiding interactions in community spaces as well as external channels
-like social media. Violating these terms may lead to a temporary or
-permanent ban.
+like social media. Violating these terms may lead to a temporary or permanent
+ban.
 
 ### 3. Temporary Ban
 
@@ -109,20 +110,24 @@ Violating these terms may lead to a permanent ban.
 standards, including sustained inappropriate behavior, harassment of an
 individual, or aggression toward or disparagement of classes of individuals.
 
-**Consequence**: A permanent ban from any sort of public interaction within
-the community.
+**Consequence**: A permanent ban from any sort of public interaction within the
+community.
 
 ## Attribution
 
 This Code of Conduct is adapted from the [Contributor Covenant][homepage],
-version 2.0, available at
-https://www.contributor-covenant.org/version/2/0/code_of_conduct.html.
+version 2.1, available at
+[https://www.contributor-covenant.org/version/2/1/code_of_conduct.html][v2.1].
 
-Community Impact Guidelines were inspired by [Mozilla's code of conduct
-enforcement ladder](https://github.com/mozilla/diversity).
-
-[homepage]: https://www.contributor-covenant.org
+Community Impact Guidelines were inspired by
+[Mozilla's code of conduct enforcement ladder][mozilla coc].
 
 For answers to common questions about this code of conduct, see the FAQ at
-https://www.contributor-covenant.org/faq. Translations are available at
-https://www.contributor-covenant.org/translations.
+[https://www.contributor-covenant.org/faq][faq]. Translations are available at
+[https://www.contributor-covenant.org/translations][translations].
+
+[homepage]: https://www.contributor-covenant.org
+[v2.1]: https://www.contributor-covenant.org/version/2/1/code_of_conduct.html
+[mozilla coc]: https://github.com/mozilla/diversity
+[faq]: https://www.contributor-covenant.org/faq
+[translations]: https://www.contributor-covenant.org/translations