Fix changelog generator parameter name from exclude-labels to excludeLabels

The action janheinrichmerker/action-github-changelog-generator@v2.3 expects
camelCase parameter names. Changed 'exclude-labels' to 'excludeLabels' in both
nightly.yml and release.yml to fix the nightly release action failure.

Co-authored-by: softhack007 <91616163+softhack007@users.noreply.github.com>

.github/workflows/nightly.yml

@@ -30,7 +30,7 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }} 
           sinceTag: v14.7.1
           # Exclude issues that were closed without resolution from changelog
-          exclude-labels: 'stale,wontfix,duplicate,invalid'
+          excludeLabels: 'stale,wontfix,duplicate,invalid'
       - name: Update Nightly Release
         uses: andelf/nightly-release@main
         env:

.github/workflows/release.yml

@@ -26,7 +26,7 @@ jobs:
           sinceTag: v14.7.1
           maxIssues: 500
           # Exclude issues that were closed without resolution from changelog
-          exclude-labels: 'stale,wontfix,duplicate,invalid'       
+          excludeLabels: 'stale,wontfix,duplicate,invalid'       
     - name: Create draft release
       uses: softprops/action-gh-release@v1
       with: