canary: bump golang from 1.21.4 to 1.21.5 in /dependabot/docker/go #300

Job	Run time
Makefile / Assert PR branch is ahead	7s
CI matrix / Assert PR branch is ahead	7s
Makefile / Build codebase using Makefile quick recipe	54s
Makefile / Build codebase using Makefile all recipe	0s
Makefile / Lint codebase using Makefile	0s
CI matrix / Lint codebase (go-ci-oldstable, false)	50s
CI matrix / Build codebase (go-ci-oldstable, false)	44s
CI matrix / Build codebase (go-ci-stable, false)	43s
CI matrix / Run tests (go-ci-oldstable, false)	50s
CI matrix / Lint codebase (go-ci-stable, false)	50s
CI matrix / Build codebase (go-ci-unstable, true)	45s
CI matrix / Run tests (go-ci-stable, false)	44s
CI matrix / Lint codebase (go-ci-unstable, true)	45s
CI matrix / Run tests (go-ci-unstable, true)	44s
CI matrix / Optional Linting / Assert PR branch is ahead	5s
CI matrix / Optional Linting / Lint codebase using optional linters (go-ci-oldstable, true)	44s
CI matrix / Optional Linting / Lint codebase using optional linters (go-ci-stable, true)	43s
CI matrix / Optional Linting / Lint codebase using optional linters (go-ci-unstable, true)	45s
	10m 20s

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