Fix CI after bazel 6.0.0 (#938)

.bazelversion

diff --git a/.bazelversion b/.bazelversion
index 91ff572..09b254e 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-5.2.0
+6.0.0

version.bzl

diff --git a/version.bzl b/version.bzl
index a73ef4d..91125c2 100644
--- a/version.bzl
+++ b/version.bzl
@@ -17,7 +17,7 @@
 # against.
 # This version should be updated together with the version of Bazel
 # in .bazelversion.
-BAZEL_VERSION = "5.2.0"
+BAZEL_VERSION = "6.0.0"
 
 # Versions of Bazel which users should be able to use.
 # Ensures we don't break backwards-compatibility,