Bump bazel version to 0.26.1

Change-Id: I4cedc7ed5ed31ac78af8c8256e580935115c7a6e
diff --git a/jenkins-docker/slave-bazel-nocache/Makefile b/jenkins-docker/slave-bazel-nocache/Makefile
index aa4315d..a5682d6 100644
--- a/jenkins-docker/slave-bazel-nocache/Makefile
+++ b/jenkins-docker/slave-bazel-nocache/Makefile
@@ -1,6 +1,6 @@
 NO_CACHE=false
 IMAGE=gerritforge/gerrit-ci-slave-bazel:debian-stretch-nocache
-BAZEL_VER=0.25.0
+BAZEL_VER=0.26.1
 BUILDIFIER_VER=0.22.0
 BAZELISK_VER=0.0.7