build: update docs and example manifests for 1.7 beta release

Signed-off-by: Travis Nielsen <tnielsen@redhat.com>

tests/scripts/github-action-helper.sh

@@ -120,7 +120,7 @@ function build_rook() {
   tests/scripts/validate_modified_files.sh build
   docker images
   if [[ "$build_type" == "build" ]]; then
-    docker tag $(docker images | awk '/build-/ {print $1}') rook/ceph:master
+    docker tag $(docker images | awk '/build-/ {print $1}') rook/ceph:v1.7.0-beta.0
   fi
 }