Update to Functions Framework v1.5.2
Update to Functions Framework v1.5.2

This contains a fix for functions using `metadata.FromContext` from the "cloud.google.com/go/functions" package.

PiperOrigin-RevId: 412118459
Change-Id: I8ac689fb9fec79c4932e7b48df83d148cb6677cb

GoogleCloudPlatform/buildpacks,GoogleCloudPlatform/buildpacks,GoogleCloudPlatform/buildpacks,GoogleCloudPlatform/buildpacks