v0.15.1 bump

[rvagg]

No description provided.

[github-actions]

Suggested version: v0.15.1

Comparing to: v0.15.0 (diff)

Changes in go.mod file(s):

(empty)

gorelease says:

# github.com/ipfs/go-graphsync/testutil
## compatible changes
TestIdentityDAG.AllLinksNoIdent: added

# diagnostics
go.sum: one or more sums are missing. Run 'go mod tidy' to add missing sums.
required module github.com/microcosm-cc/bluemonday@v1.0.1 retracted by module author: Retract older versions as only latest is to be depended upon

# summary
Suggested version: v0.16.0

gocompat says:

Your branch is up to date with 'origin/main'.

Automatically created GitHub Release

A draft GitHub Release has been created.
It is going to be published when this PR is merged.
You can modify its' body to include any release notes you wish to include with the release.

[rvagg]

## compatible changes
TestIdentityDAG.AllLinksNoIdent: added

I'm calling this a bugfix; plus it's only in the testutil package