Update Prometheus dependency to latest release (v2.40.4)

[rfratto]

Closes #7811, which is needed for Grafana Agent to update to v2.40 and add support for native histograms.

I did not add support for native histograms to Loki, sorry :)

[rfratto]

Hm, this is failing on the protobufs:

github.com/weaveworks/common/httpgrpc/httpgrpc.proto: Import "gogoproto/gogo.proto" was not found or had errors.
pkg/lokifrontend/frontend/v1/frontendv1pb/frontend.proto: Import "github.com/weaveworks/common/httpgrpc/httpgrpc.proto" was not found or had errors.
pkg/lokifrontend/frontend/v1/frontendv1pb/frontend.proto:30:3: "httpgrpc.HTTPRequest" is not defined.
pkg/lokifrontend/frontend/v1/frontendv1pb/frontend.proto:39:3: "httpgrpc.HTTPResponse" is not defined.

I'm not sure what I should do here; I think it might be related to @krajorama's resent changes to weaveworks/common but I can't tell.

[krajorama]

Hm, this is failing on the protobufs:

github.com/weaveworks/common/httpgrpc/httpgrpc.proto: Import "gogoproto/gogo.proto" was not found or had errors.
pkg/lokifrontend/frontend/v1/frontendv1pb/frontend.proto: Import "github.com/weaveworks/common/httpgrpc/httpgrpc.proto" was not found or had errors.
pkg/lokifrontend/frontend/v1/frontendv1pb/frontend.proto:30:3: "httpgrpc.HTTPRequest" is not defined.
pkg/lokifrontend/frontend/v1/frontendv1pb/frontend.proto:39:3: "httpgrpc.HTTPResponse" is not defined.

I'm not sure what I should do here; I think it might be related to @krajorama's resent changes to weaveworks/common but I can't tell.

Yes, we've fixed non-reproducable build in weaveworks/common#264 and weaveworks/common#265 . See comment here on knock on effect: weaveworks/common#262 (comment)

TL;DR; you need to have a -I include directive for protoc to find gogoproto/gogo.proto

[rfratto]

@krajorama Thanks! Looks like there was two set of issues:

1. I needed to add the -I directive for gogoproto/gogo.proto as you mentioned
2. I needed to update Loki protos to import gogoproto/gogo.proto instead of the full path, otherwise it caused a collision from protoc and failed to compile.

[grafanabot]

./tools/diff_coverage.sh ../loki-target-branch/test_results.txt test_results.txt ingester,distributor,querier,querier/queryrange,iter,storage,chunkenc,logql,loki

Change in test coverage per package. Green indicates 0 or positive change, red indicates that test coverage for a package fell.

+           ingester	0%
+        distributor	0%
+            querier	0%
+ querier/queryrange	0%
+               iter	0%
+            storage	0%
+           chunkenc	0%
+              logql	0%
+               loki	0%

[slim-bean]

thanks for putting in all the effort to make this change @rfratto !