Bump Bazel to 4.0.0

This bumps Bazel to 4.0.0 because we want to use ProtoModule. The update was relatively painless,
no incompat-flags needed to be switched back off. `bazel_gazelle` is pinned on a master version
since they haven't released a Bazel 4-comaptible version yet and I have one patch against Kubernetes's
infra repo which is going upstream.

Test Plan: Build system change, should be covered by existing tests

X-Origin-Diff: phab/D701
GitOrigin-RevId: 24f675e6ba33efb9f46191eccca95088d7d2d1f1
diff --git a/build/Dockerfile b/build/Dockerfile
index b893eec..8935d1f 100644
--- a/build/Dockerfile
+++ b/build/Dockerfile
@@ -37,8 +37,8 @@
 
 # Install Bazel binary
 RUN curl -o /usr/local/bin/bazel \
-	https://releases.bazel.build/3.7.2/release/bazel-3.7.2-linux-x86_64 && \
-	echo '70dc0bee198a4c3d332925a32d464d9036a831977501f66d4996854ad4e4fc0d  /usr/local/bin/bazel' | sha256sum --check && \
+	https://releases.bazel.build/4.0.0/release/bazel-4.0.0-linux-x86_64 && \
+	echo '7bee349a626281fc8b8d04a7a0b0358492712377400ab12533aeb39c2eb2b901  /usr/local/bin/bazel' | sha256sum --check && \
 	chmod +x /usr/local/bin/bazel
 
 # Use a shared Go module cache for gazelle