Go: auto-bump go version

[maxday]

In order to reduce maintenance effort (see: #1812), it would be great to see go version to be auto-bumped.

I think there are two sub tasks for this:

1. Remove hardcoded go-version in GitHub Actions worflows as it can lead to version mismatch, ie on main today: https://github.com/open-telemetry/opentelemetry-lambda/blob/3af180dc7f9dde4e06a939bd794b0430840dcddd/.github/workflows/ci-collector.yml#L27 and https://github.com/open-telemetry/opentelemetry-lambda/blob/3af180dc7f9dde4e06a939bd794b0430840dcddd/.github/workflows/ci-python.yml#L51
2. Use a GitHub action to auto-bump go.mod go version. Unfortunately that's not yet supported by Dependabot (source: https://github.com/dependabot/dependabot-core/issues/9057)

I will tackle both of these Thanks!