add RBE setup platforms to run the following

$ bazel run   --config=remote-ubuntu-22-04   --platforms=//tests/support/remote-toolchains:ubuntu-act-22-04-platform   //docs:requirements.update

Author: aignas

.bazelrc

@@ -35,4 +35,30 @@ build:rtd --enable_bzlmod
 
 common --incompatible_python_disallow_native_rules
 
+### TODO @aignas 2025-03-22: remove?
+#
 build --lockfile_mode=update
+
+# Only download the final result, the intermediate files can stay on the
+# server side.
+build --remote_download_toplevel
+
+# Kubernetes will have a different host name than 'localhost'.
+build:remote-exec --remote_executor=grpc://localhost:8980
+# The Buildbarn worker can configure instance_name_prefix to create separate
+# execution bins within the cluster. Optional, but useful when trying new
+# worker configurations.
+build:remote-exec --remote_instance_name=fuse
+# Make sure to load Buildbarn with more requests than the number of CPUs on
+# your host machine.
+build:remote-exec --jobs=64
+# Make sure that the remote execution platform and the matching toolchains
+# take precedence over the other definitions in the WORKSPACE file.
+#build:remote-exec --extra_toolchains=//tests/support/remote-toolchains:all
+
+# When running Ubuntu 22.04 executors.
+build:remote-ubuntu-22-04 --config=remote-exec
+build:remote-ubuntu-22-04 --extra_execution_platforms=//tests/support/remote-toolchains:ubuntu-act-22-04-platform
+
+# When running bare executors on your own host machine.
+build:remote-local --config=remote-exec

tests/support/remote-toolchains/BUILD.bazel

@@ -0,0 +1,23 @@
+constraint_setting(
+    name = "container-image",
+)
+
+constraint_value(
+    name = "ubuntu-act-22-04",
+    constraint_setting = ":container-image",
+)
+
+REMOTE_EXEC_CONSTRAINTS = [
+    "@platforms//cpu:x86_64",
+    "@platforms//os:linux",
+    ":ubuntu-act-22-04",
+]
+
+platform(
+    name = "ubuntu-act-22-04-platform",
+    constraint_values = REMOTE_EXEC_CONSTRAINTS,
+    exec_properties = {
+        "OSFamily": "linux",
+        "container-image": "docker://ghcr.io/catthehacker/ubuntu:act-22.04@sha256:5f9c35c25db1d51a8ddaae5c0ba8d3c163c5e9a4a6cc97acd409ac7eae239448",
+    },
+)