[UIMA-6293] Migrate UIMA Parent POM to GitHub

- Move tag to new location

git-svn-id: https://svn.apache.org/repos/asf/uima/build/parent-pom/tags/parent-pom-8@1883119 13f79535-47bb-0310-9956-ffa450edef68
tree: 9a4eb9e873bb7969afe8d4119c16dc6f6c6f777f
  1. README.txt
  2. marker-file-identifying-parent-pom
  3. pom.xml