Bump bazel version to 4.0.0

Fix Bazelisk build incomptaibility with bazel 4.0.0 and temporarily
un-flip the option: --incompatible_restrict_string_escapes=false.

See also this bazelisk issue: [1] for more background.

[1] https://github.com/bazelbuild/bazelisk/issues/213

Change-Id: I5a4eeccc6d2dd5a80e0e4b43fb9c04a55d316e06
diff --git a/jenkins-docker/slave-bazel-nocache/Dockerfile b/jenkins-docker/slave-bazel-nocache/Dockerfile
index c1a2f24..daab49b 100644
--- a/jenkins-docker/slave-bazel-nocache/Dockerfile
+++ b/jenkins-docker/slave-bazel-nocache/Dockerfile
@@ -22,12 +22,14 @@
     buildifier --version'
 
 # Install Bazelisk
+# TODO:(davido) Remove --incompatible_restrict_string_escapes=false, when this is fixed:
+# https://github.com/bazelbuild/bazelisk/issues/213
 RUN cd /tmp && \
     git clone https://github.com/bazelbuild/bazelisk.git && \
     cd bazelisk && \
     git checkout v${BAZELISK_VER} && \
     rm -f .bazelversion && \
-    bazel build --stamp --workspace_status_command=`pwd`/stamp.sh --platforms=@io_bazel_rules_go//go/toolchain:linux_amd64 //:bazelisk && \
+    bazel build --config=release --incompatible_restrict_string_escapes=false //:bazelisk && \
     cp bazel-bin/*/bazelisk /usr/bin && \
     rm -rf /tmp/bazelisk
 
diff --git a/jenkins-docker/slave-bazel-nocache/Makefile b/jenkins-docker/slave-bazel-nocache/Makefile
index 30b09f3..8504915 100644
--- a/jenkins-docker/slave-bazel-nocache/Makefile
+++ b/jenkins-docker/slave-bazel-nocache/Makefile
@@ -2,7 +2,7 @@
 
 NO_CACHE=false
 IMAGE=gerritforge/gerrit-ci-slave-bazel:debian-buster-nocache
-BAZEL_VER=3.7.0
+BAZEL_VER=4.0.0
 BUILDIFIER_VER=3.5.0
 BAZELISK_VER=1.7.4
 NODE_VER=10