chore(deps): bump github.com/sigstore/sigstore from 1.8.3 to 1.8.4 (#… #1025

Job	Run time
examples / client (ubuntu-latest)	18s
examples / multirepo (ubuntu-latest)	16s
examples / client (macos-latest)	18s
examples / multirepo (macos-latest)	18s
examples / client (windows-latest)	1m 48s
examples / multirepo (windows-latest)	1m 56s
examples / repository (ubuntu-latest)	18s
examples / root-signing (ubuntu-latest)	24s
examples / repository (macos-latest)	27s
examples / root-signing (macos-latest)	23s
examples / repository (windows-latest)	1m 37s
examples / root-signing (windows-latest)	1m 38s
examples / tuf-client-cli (ubuntu-latest)	19s
linting / golangci-lint	2m 40s
linting / govulncheck	24s
examples / tuf-client-cli (macos-latest)	23s
examples / tuf-client-cli (windows-latest)	2m 32s
tests / Run (ubuntu-latest)	29s
tests / Run (macos-latest)	33s
tests / Run (windows-latest)	1m 54s
	18m 55s

Provide feedback