Mixin: Pin the mixtool version in CircleCI

In mixtool, the tip of master broke for our mixin - I have managed to trace it down and opened a PR (see https://github.com/grafana/dashboard-linter/pull/143) but for now, let's pin the version to make sure our CI is not affected.

Signed-off-by: gotjosh <josue.abreu@gmail.com>

.circleci/config.yml

@@ -107,7 +107,8 @@ jobs:
       - image: quay.io/prometheus/golang-builder:1.20-base
     steps:
       - checkout
-      - run: go install github.com/monitoring-mixins/mixtool/cmd/mixtool@latest
+      # pin the mixtool version until https://github.com/monitoring-mixins/mixtool/issues/135 is merged.
+      - run: go install github.com/monitoring-mixins/mixtool/cmd/mixtool@2282201396b69055bb0f92f187049027a16d2130
       - run: go install github.com/google/go-jsonnet/cmd/jsonnetfmt@latest
       - run: go install github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb@latest
       - run: make -C doc/alertmanager-mixin lint

doc/alertmanager-mixin/Makefile

@@ -20,7 +20,6 @@ lint: build
 
 	mixtool lint mixin.libsonnet
 
-
 dashboards_out: mixin.libsonnet config.libsonnet $(wildcard dashboards/*)
 	@mkdir -p dashboards_out
 	jsonnet -J vendor -m dashboards_out dashboards.jsonnet