use java 21 in tests, remove mention of main branch

.gitlab-ci.yml

@@ -12,7 +12,7 @@ cache:
     - .gradle/caches
 
 build:
-  image: openjdk:8
+  image: eclipse-temurin:21
   stage: build
   script:
     - ./gradlew --console=plain --no-daemon assemble fatJar
@@ -21,7 +21,7 @@ build:
       - "/builds/jastadd/relational-rags/build/libs/relast-*.jar"
 
 test:
-  image: openjdk:8
+  image: eclipse-temurin:21
   stage: test
   script:
     - ./gradlew --console=plain --no-daemon --info test
@@ -36,22 +36,20 @@ pages:
     paths:
     - public
   only:
-    - master
     - main
 
 publish:
-  image: openjdk:8
+  image: eclipse-temurin:21
   stage: deploy
   needs:
     - test
   script:
     - "./gradlew publish"
   only:
-    - master
     - main
 
 publish_dev:
-  image: openjdk:8
+  image: eclipse-temurin:21
   stage: deploy
   needs:
     - test
@@ -59,5 +57,4 @@ publish_dev:
     - "./gradlew setDevVersionForCI"
     - "./gradlew publish"
   except:
-    - master
     - main