[PORT] Remove SHA1 for support for ssh rsa signing (#31857) (#5303)

https://github.com/go-fed/httpsig seems to be unmaintained.

Switch to github.com/42wim/httpsig which has removed deprecated crypto
and default sha256 signing for ssh rsa.

No impact for those that use ed25519 ssh certificates.

This is a breaking change for:
- gitea.com/gitea/tea (go-sdk) - I'll be sending a PR there too
- activitypub using deprecated crypto (is this actually used?)

(cherry picked from commit 01dec7577a051d9bb30e91f6cf6653dc51a37d06)

---
Conflict resolution: trivial

Co-authored-by: Wim <wim@42.be>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/5303
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>

go.sum

@@ -919,8 +919,8 @@ github.com/go-faster/city v1.0.1 h1:4WAxSZ3V2Ws4QRDrscLEDcibJY8uf41H6AhXDrNDcGw=
 github.com/go-faster/city v1.0.1/go.mod h1:jKcUJId49qdW3L1qKHH/3wPeUstCVpVSXTM6vO3VcTw=
 github.com/go-faster/errors v0.7.1 h1:MkJTnDoEdi9pDabt1dpWf7AA8/BaSYZqibYyhZ20AYg=
 github.com/go-faster/errors v0.7.1/go.mod h1:5ySTjWFiphBs07IKuiL69nxdfd5+fzh1u7FPGZP2quo=
-github.com/go-fed/httpsig v1.1.1-0.20201223112313-55836744818e h1:oRq/fiirun5HqlEWMLIcDmLpIELlG4iGbd0s8iqgPi8=
-github.com/go-fed/httpsig v1.1.1-0.20201223112313-55836744818e/go.mod h1:RCMrTZvN1bJYtofsG4rd5NaO5obxQ5xBkdiS7xsT7bM=
+github.com/go-fed/httpsig v1.1.0 h1:9M+hb0jkEICD8/cAiNqEB66R87tTINszBRTjwjQzWcI=
+github.com/go-fed/httpsig v1.1.0/go.mod h1:RCMrTZvN1bJYtofsG4rd5NaO5obxQ5xBkdiS7xsT7bM=
 github.com/go-fonts/dejavu v0.1.0/go.mod h1:4Wt4I4OU2Nq9asgDCteaAaWZOV24E+0/Pwo0gppep4g=
 github.com/go-fonts/latin-modern v0.2.0/go.mod h1:rQVLdDMK+mK1xscDwsqM5J8U2jrRa3T0ecnM9pNujks=
 github.com/go-fonts/liberation v0.1.1/go.mod h1:K6qoJYypsmfVjWg8KOVDQhLc8UDgIK2HYqyqAO9z7GY=