Bump Golang to go1.16.6

[cf-diego]

Remember to also bump the following submodules:

• golang.org/x/crypto
• golang.org/x/net
• golang.org/x/sys
• golang.org/x/text
• golang.org/x/time
• golang.org/x/tools
• golang.org/x/mod
• golang.org/x/xerrors

Bump Dockerfile golang version

• Example bump for previous go version
• Sync pipelines

Acceptance

• Check the progress of the bump in diego-ci. Confirm all jobs have passed and release-candidate branch has been bumped

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. Unfortunately, the Pivotal Tracker project is private so you may be unable to view the contents of the story.

The labels on this github issue will be updated when the story is started.

[linux-foundation-easycla]

• ❌ - Cloud Foundry Diego The commit (c4c2680) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.