[receiver/githubreceiver] add githubreceiver alpha component to manifest

[adrielp]

No description provided.

[adrielp]

Corresponding promotion of component to alpha status open-telemetry/opentelemetry-collector-contrib#34960

[adrielp]

I preemptively set the version to v0.109.0 so that it could be merged in as part of the next release. The githubreceiver was renamed from the gitproviderreceiver and then promoted to alpha so if I had set as v0.108.0 the workflows would fail, and of course at time of writing, v0.109.0 hasn't been cut yet. If able, please merge in as part of v0.109.0 release.

[TylerHelmuth]

@adrielp I reran CI after contrib's release, but things still failed.

[adrielp]

@TylerHelmuth - the workflow looked odd, like a failure due to the strict flag on the builder (I didn't look too far in the log or action). Looks like it's being added in via this commit though #660 (comment) which may just wor.k. I'll close this PR if it's being added in the other and if it failed there too (i see the correct tags on contrib for go mod versioning to work) then can take a deeper look at open another pr.