CHANGELOG. Replace GH-* by links to issues

CHANGELOG.md

@@ -1,19 +1,16 @@
 # M2 (Dec 2020)
    * Swing interoperability support (Compose in Swing frame)
    * Support of [XML vector images](https://developer.android.com/guide/topics/graphics/vector-drawable-resources)
-   * Support for Gradle 6.6 and 6.7 (GH-66)
-   * Support macOS 10.13 and 10.14 (GH-76)
+   * Support for Gradle 6.6 and 6.7 (https://github.com/JetBrains/compose-jb/issues/66)
+   * Support macOS 10.13 and 10.14 (https://github.com/JetBrains/compose-jb/issues/76)
    * Support Apple Silicon (am64) natively
-   * Support letter spacing in text (GH-82)
-   * Implemented desktop "ActualDialog" and "ActualPopup" (GH-19, GH-81)
-   * Fix input method bar positioning (GH-67)
-   * Fix text alignment (GH-92)
-   * Fix dropdown/popup positioning (GH-139)
-   * Fix using with Compose in same app as Java FX (GH-17)
-   * Added screenshots of example apps (GH-90)
+   * Support letter spacing in text (https://github.com/JetBrains/compose-jb/issues/82)
+   * Implemented desktop "ActualDialog" and "ActualPopup" (https://github.com/JetBrains/compose-jb/issues/19, https://github.com/JetBrains/compose-jb/issues/81)
+   * Fix input method bar positioning (https://github.com/JetBrains/compose-jb/issues/67)
+   * Fix text alignment (https://github.com/JetBrains/compose-jb/issues/92)
+   * Fix dropdown/popup positioning (https://github.com/JetBrains/compose-jb/issues/139)
+   * Fix using with Compose in same app as Java FX (https://github.com/JetBrains/compose-jb/issues/17)
+   * Added screenshots of example apps (https://github.com/JetBrains/compose-jb/issues/90)
 
 # M1 (Nov 2020)
    * Initial release
-
-### Legend
-   * GH-XXX - issue in GitHub repository https://github.com/JetBrains/compose-jb/issues/<XXX>