Increase version count for google3 releasees

An extra version was added here:
https://critique.corp.google.com/cl/576790948

Change-Id: If7610b258399495bc06d2bbd259f9d3da9b0c228
diff --git a/tools/r8_release.py b/tools/r8_release.py
index 8aaca29..8737ef3 100755
--- a/tools/r8_release.py
+++ b/tools/r8_release.py
@@ -437,7 +437,7 @@
                 result = re.search(version_match_regexp, line)
                 if result:
                     match_count = match_count + 1
-            if match_count != 7:
+            if match_count != 8:
                 print((
                     "Could not find the previous -dev release string to replace in "
                     + "METADATA. Expected to find is mentioned 7 times, but " +