[Snyk] Security upgrade golang from 1.18 to 1.20

[mefellows]

This PR was automatically created by Snyk using the credentials of a real user.

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

Changes included in this PR

• Dockerfile

We recommend upgrading to golang:1.20, as this image has only 134 known vulnerabilities. To do this, merge this pull request, then verify your application still works as expected.

Some of the most important vulnerabilities in your base image include:

Severity	Priority Score / 1000	Issue	Exploit Maturity
	714	Exposure of Resource to Wrong Sphere SNYK-DEBIAN11-CURL-3065656	No Known Exploit
	614	Uncontrolled Search Path Element SNYK-DEBIAN11-GIT-2635965	No Known Exploit
	714	Integer Overflow or Wraparound SNYK-DEBIAN11-GIT-3232722	No Known Exploit
	714	Integer Overflow or Wraparound SNYK-DEBIAN11-GIT-3232724	No Known Exploit
	686	Allocation of Resources Without Limits or Throttling SNYK-DEBIAN11-OPENSSL-5661566	No Known Exploit

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🦉 Allocation of Resources Without Limits or Throttling

[coveralls]

coverage: 77.52%. remained the same when pulling 4b7c82b on snyk-fix-d6ac2e6413ba2f60946c6dcd9b818635 into 88a372a on master.

[YOU54F]

closed in favour of #305