Update Unity build workflow credentials and version

Replaces UNITY_LICENSE_2020 with UNITY_LICENSE, adds UNITY_EMAIL and UNITY_PASSWORD environment variables, and sets unityVersion to 2021.3.45f2 for the build job.

Author: mackysoft

.github/workflows/build.yaml

@@ -41,6 +41,9 @@ jobs:
       - name: Build
         uses: game-ci/unity-builder@v4
         env:
-          UNITY_LICENSE: ${{ secrets.UNITY_LICENSE_2020 }}
+          UNITY_LICENSE: ${{ secrets.UNITY_LICENSE }}
+          UNITY_EMAIL: ${{ secrets.UNITY_EMAIL }}
+          UNITY_PASSWORD: ${{ secrets.UNITY_PASSWORD }}
         with:
           targetPlatform: ${{ matrix.targetPlatform }}
+          unityVersion: 2021.3.45f2