Enable immutable releases

[martincostello]

See open-telemetry/opentelemetry-dotnet#6748 for context.

We may have to tweak the release process here depending on how gh release create works. Unlike in opentelemetry-dotnet, we do not create the releases as drafts:

opentelemetry-dotnet-contrib/build/scripts/post-release.psm1

Lines 71 to 87 in 8055345

	if ($version -match '-alpha' -or $version -match '-beta' -or $version -match '-rc')
	{
	gh release create $tag $releaseFiles `
	--title $tag `
	--verify-tag `
	--notes $notes `
	--prerelease
	}
	else
	{
	gh release create $tag $releaseFiles `
	--title $tag `
	--verify-tag `
	--notes $notes `
	--latest
	}
	}

If gh release does not internally create a draft, upload the files, then un-draft, the release will lack the required assets attached to it, but then be undeletable and unable to have them manually added.

If it does handle that internally, there's nothing we'd need to change in the release process, but otherwise we would need to add --draft to each invocation above, and then add gh release edit $tag --draft=false immediately afterwards.

[martincostello]

Immutable releases are now enabled.

Instrumentation.AWS-1.14.1 is the first.