Use temurin instead of adopt (#868)

See
https://blog.adoptopenjdk.net/2021/08/goodbye-adoptopenjdk-hello-adoptium/.

.github/workflows/ci.yml

@@ -20,8 +20,7 @@ jobs:
         uses: actions/setup-java@v3
         with:
           java-version: '8'
-          distribution: 'adopt'
-          
+          distribution: 'temurin'
 
       - name: Cache Gradle dependencies
         uses: actions/cache@v3

.github/workflows/docs.yml

@@ -15,7 +15,7 @@ jobs:
         uses: actions/setup-java@v3
         with:
           java-version: '8'
-          distribution: 'adopt'
+          distribution: 'temurin'
 
       - name: Cache Gradle dependencies
         uses: actions/cache@v3