Update go version to v1.15.13

[michel-laterman]

What does this PR do?

Update go version used to compile to 1.15.13

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Related issues

• Relates Update to golang 1.16.5/1.15.13 #26182

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• Build Cause: michel-laterman commented: /test

• Start Time: 2021-06-09T15:32:32.497+0000

• Duration: 8 min 23 sec

• Commit: 64091d5

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[michel-laterman]

/test

[michel-laterman]

/test