Add CHANGELOG entry.

This really shouldn't be in the CHANGELOG since it isn't user facing,
but the firehose script complains if the pubspec version doesn't match
the CHANGELOG.

Also, update the GitHub workflow to run against 3.6.0.

Author: munificent

.github/workflows/test-package.yml

@@ -20,7 +20,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        sdk: [3.4.0, dev]
+        sdk: [3.6.0, dev]
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: dart-lang/setup-dart@e630b99d28a3b71860378cafdc2a067c71107f94

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.0.2-wip
+
+* Add tests for digit separators.
+
 ## 3.0.1
 
 * Handle trailing commas in for-loop updaters (#1354).