Drop Flink 1.17,1.18 support

Author: Abacn

.github/actions/setup-default-test-properties/test-properties.json

@@ -14,7 +14,7 @@
   },
   "JavaTestProperties": {
     "SUPPORTED_VERSIONS": ["8", "11", "17", "21", "25"],
-    "FLINK_VERSIONS": ["1.17", "1.18", "1.19", "1.20", "2.0", "2.1"],
+    "FLINK_VERSIONS": ["1.19", "1.20", "2.0", "2.1"],
     "SPARK_VERSIONS": ["3"]
   },
   "GoTestProperties": {

gradle.properties

@@ -39,7 +39,7 @@ docker_image_default_repo_root=apache
 docker_image_default_repo_prefix=beam_
 
 # supported flink versions
-flink_versions=1.17,1.18,1.19,1.20,2.0,2.1
+flink_versions=1.19,1.20,2.0,2.1
 # supported spark versions
 spark_versions=3,4
 # supported python versions