Update secure test projects to reference gemnasium in DS_REPORT_URL

Proposal

Now that Remove code (moved to gemnasium project) (gitlab-org/security-products/analyzers/gemnasium-maven!195 - merged) and Remove code (moved to gemnasium project) (gitlab-org/security-products/analyzers/gemnasium-python!179 - merged) have been merged, and all related code has been moved to the gemnasium project, we've started encountering failing tests. We need to update the DS_REPORT_URL in the .gitlab-ci.yml for the tests projects and replace references to gemnasium-maven and gemnasium-python with gemnasium to fix these broken tests.

In total, there are 10 test projects and 29 branches that need to be updated:

• java-maven
  • update-expectation-maven-cli-opts-skip-tests-FREEZE
  • offline-FREEZE
  • maven-cli-opts-skip-tests-FREEZE
  • master
  • custom-ca-cert-java-8-FREEZE
• python-pip
  • offline-FREEZE
  • master
• java-maven-multimodules
  • semgrep-migration-FREEZE
  • offline-FREEZE
  • master
• scala-sbt
  • sbt-cli-opts-FREEZE
  • offline-FREEZE
  • master
• java-gradle
  • offline-FREEZE
  • master
  • gradle-cli-opts-FREEZE
• python-pipenv
  • require-system-python-FREEZE
  • pipfile-lock-FREEZE
  • offline-FREEZE
  • master
• java-gradle-multimodules
  • subprojects-buildfilename-FREEZE
  • offline-FREEZE
  • no-root-dependencies-FREEZE
  • master
• java-gradle-kotlin-dsl
  • offline-FREEZE
  • master
• scala-sbt-multiproject
  • main
• python-setuptools
  • offline-FREEZE
  • main

/cc @fcatteau @gonzoyumo