CHANGELOG: describe recent changes for 1.0.0

Describe changes from commits [1] and [2] in CHANGELOG.md in preparation
for the upcoming release.

[1] 42ed6df (Gradle: jar: include LICENSE.txt in META-INF, 2023-07-08)
[2] b948db4 (CopyCommitReferenceAction: make ProgressIndicator
    determinate, 2023-07-08)

CHANGELOG.md

@@ -5,9 +5,15 @@
 ## [Unreleased]
 
 ### Added
-- If commit's subject line contains mentions of issues, which are configured for
+- If a commit's subject line contains mentions of issues, which are configured for
   [navigation in the project](https://www.jetbrains.com/help/idea/settings-version-control-issue-navigation.html),
   then the reference pasted into a rich text editor will include clickable links.
+- [LICENSE.txt](https://github.com/rybak/intellij-copy-commit-reference/blob/main/LICENSE.txt)
+  is now included as part of the plugin's jar file.
+
+### Fixed
+- Warning caused by incorrect usage of `com.intellij.openapi.progress.ProgressIndicator`
+  has been fixed.
 
 ## [0.3.0-alpha] - 2023-07-07