[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-7@1883118 13f79535-47bb-0310-9956-ffa450edef68
tree: 1d27ecd0904b7bee56cc7d1496a1cc8caf85bf20
  1. README.txt
  2. marker-file-identifying-parent-pom
  3. pom.xml