[Snyk] Security upgrade golang from 1.20.13 to 1.21.12

[xcaspar]

Snyk has created this PR to fix 4 vulnerabilities in the dockerfile dependencies of this project.

Keeping your Docker base image up-to-date means you’ll benefit from security fixes in the latest version of your chosen image.

Snyk changed the following file(s):

• build/image/musl/Dockerfile

We recommend upgrading to golang:1.21.12, as this image has only 89 known vulnerabilities. To do this, merge this pull request, then verify your application still works as expected.

Vulnerabilities that will be fixed with an upgrade:

	Issue	Score
	Improper Verification of Cryptographic Signature SNYK-DEBIAN12-GNUTLS28-6159410	614
	Information Exposure SNYK-DEBIAN12-GNUTLS28-6159418	614
	Improper Input Validation SNYK-DEBIAN12-PYTHON311-3325304	614
	Untrusted Search Path SNYK-DEBIAN12-PYTHON311-5853785	614
	Untrusted Search Path SNYK-DEBIAN12-PYTHON311-5853785	614

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[!IMPORTANT]

• Check the changes in this PR to ensure they won't cause issues with your project.
• Max score is 1000. Note that the real score may have changed since the PR was raised.
• This PR was automatically created by Snyk using the credentials of a real user.

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Learn how to fix vulnerabilities with free interactive lessons:

🦉 Improper Input Validation