Update to 3.7

Build against 3.7.0 and test against 3.7.6. Also update the bazel
version to match core stable-3.7.

Change-Id: I7597d120838e54ed1c0ac3220b22f32fbeeae9db

.bazelversion

diff --git a/.bazelversion b/.bazelversion
index c7cb131..6abaeb2 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-5.3.1
+6.2.0

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 989ddb9..c5a30fc 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "ea5aa9f256fe94577accb074f1f51e12af106708",
+    commit = "4b1d0d1c0ec0c27db25eaf111c7ea07aecb13742",
 )
 
 load(

test/docker/gerrit/Dockerfile

diff --git a/test/docker/gerrit/Dockerfile b/test/docker/gerrit/Dockerfile
index 127b922..0859d90 100755
--- a/test/docker/gerrit/Dockerfile
+++ b/test/docker/gerrit/Dockerfile
@@ -1,4 +1,4 @@
-FROM gerritcodereview/gerrit:3.6.8-ubuntu20
+FROM gerritcodereview/gerrit:3.7.6-ubuntu20
 
 ENV GERRIT_SITE /var/gerrit
 COPY artifacts/plugins/ $GERRIT_SITE/plugins/