Add more detail to the comment explaining the required secrets

Signed-off-by: Jade Carino <[email protected]>

.github/workflows/build.yaml

@@ -26,7 +26,8 @@ jobs:
       - name: Check if WRITE_GITHUB_PACKAGES_USERNAME is set in this repository
         run: |
           if [ -z "${{ secrets.WRITE_GITHUB_PACKAGES_USERNAME }}" ]; then
-            echo "WRITE_GITHUB_PACKAGES_USERNAME is not set. Please configure it in the repository secrets."
+            echo "WRITE_GITHUB_PACKAGES_USERNAME is not set. Please configure it in the repository secrets. \
+            It must contain the GitHub username you want to use to log into GitHub Container Registry."
             exit 1
           else
             echo "WRITE_GITHUB_PACKAGES_USERNAME is set."
@@ -35,7 +36,9 @@ jobs:
       - name: Check if WRITE_GITHUB_PACKAGES_TOKEN is set in this repository
         run: |
           if [ -z "${{ secrets.WRITE_GITHUB_PACKAGES_TOKEN }}" ]; then
-            echo "WRITE_GITHUB_PACKAGES_TOKEN is not set. Please configure it in the repository secrets."
+            echo "WRITE_GITHUB_PACKAGES_TOKEN is not set. Please configure it in the repository secrets. \
+            It must contain a GitHub Personal Access Token with write:packages scope \
+            that you want to use to log into GitHub Container Registry.""
             exit 1
           else
             echo "WRITE_GITHUB_PACKAGES_TOKEN is set."