Update common Prometheus files (#915)

Signed-off-by: prombot <prometheus-team@googlegroups.com>

config: apply DialContextFunc to OAuth2 token-fetch transport (#911)

newOauth2TokenSource builds its own http.Transport to fetch tokens but
doesn't set DialContext on it. Any DialContextFunc passed via
WithDialContextFunc is applied to the main request transport but silently
skipped for the token endpoint.

Set DialContext on the token transport the same way it is set on the main
one. When dialContextFunc is nil the behaviour is unchanged since
http.Transport falls back to its default dialer.

Added TestOAuth2DialContextFunc to verify that WithDialContextFunc blocks
the token endpoint fetch, not only the final request.

Signed-off-by: Yuri Tseretyan <yuriy.tseretyan@grafana.com>

build(deps): bump google.golang.org/protobuf from 1.36.10 to 1.36.11 (#…

…870)

Bumps google.golang.org/protobuf from 1.36.10 to 1.36.11.

---
updated-dependencies:
- dependency-name: google.golang.org/protobuf
  dependency-version: 1.36.11
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

chore: Add omitempty tag to all config fields (#865)

* chore: Add omitempty tag to all config fields

Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz>

* chore: Add omitempty tag to all config fields

Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz>

* chore: Add omitempty tag to all config fields

Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz>

---------

Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz>

Merge pull request #863 from prometheus/remove-http2-comment

Config: remove outdated comment about HTTP/2 issues

Merge pull request #853 from prometheus/superq/version

Fix Go case-insensitive file name collision