Merge branch 'stable-5.7'

* stable-5.7:
  Bump required Bazel version to 2.1.0
  Upgrade bazlets to the latest master revision
  Change the wildcard import to explicit ones.

Change-Id: I5aeaad53ac729e2dcfa67c6830accee749cd21cd
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

.bazelversion

@@ -1 +1 @@
-2.0.0
+2.1.0

WORKSPACE

@@ -20,7 +20,7 @@ check_bazel_version()
 
 load("//tools:bazlets.bzl", "load_bazlets")
 
-load_bazlets(commit = "f53f51fb660552d0581aa0ba52c3836ed63d56a3")
+load_bazlets(commit = "f30a992da9fc855dce819875afb59f9dd6f860cd")
 
 load(
     "@com_googlesource_gerrit_bazlets//tools:maven_jar.bzl",