Pin exact version of external ci actions

.github/workflows/appimage.yml

@@ -185,7 +185,7 @@ jobs:
           if-no-files-found: error
       - name: Publish AppImage on GitHub Releases
         if: startsWith(github.ref, 'refs/tags/') && github.event.action == 'published'
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@6da8fa9354ddfdc4aeace5fc48d7f679b5214090
         with:
           fail_on_unmatched_files: true
           token: ${{ secrets.CRYPTOBOT_RELEASE_TOKEN }}
@@ -247,7 +247,7 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.CRYPTOBOT_PR_TOKEN }}
       - name: Slack Notification
-        uses: rtCamp/action-slack-notify@v2
+        uses: rtCamp/action-slack-notify@e31e87e03dd19038e411e38ae27cbad084a90661
         env:
           SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK_URL }}
           SLACK_USERNAME: 'Cryptobot'