Remove ubuntu18 as rules_proto absiel version doesn't support it

Author: restingbull

.bazelci/presubmit.yml

@@ -2,10 +2,8 @@
 matrix:
   unittest_platform:
     - ubuntu2004
-    - ubuntu1804
   integration_platform:
     - ubuntu2004
-    - ubuntu1804
     # - macos
     # - windows re-enable when rules_bazel_integration_test can support custom test runner on windows.
   test_flags:

MODULE.bazel

@@ -99,8 +99,8 @@ maven.override(
 use_repo(maven, "kotlin_rules_maven", "unpinned_kotlin_rules_maven")
 
 bazel_dep(name = "rules_pkg", version = "1.0.1")
+bazel_dep(name = "rules_proto", version = "7.0.2")
 bazel_dep(name = "stardoc", version = "0.7.2", repo_name = "io_bazel_stardoc")
-bazel_dep(name = "rules_proto", version = "5.3.0-21.7")
 
 bazel_dep(name = "rules_testing", version = "0.5.0", dev_dependency = True)
 bazel_dep(name = "rules_bazel_integration_test", version = "0.25.0", dev_dependency = True)