chore(deps): bump github.com/akuity/bookkeeper

Bumps [github.com/akuity/bookkeeper](https://github.com/akuity/bookkeeper) from 0.1.0-rc.19 to 0.1.0-rc.21.
- [Release notes](https://github.com/akuity/bookkeeper/releases)
- [Commits](akuity/kargo-render@v0.1.0-rc.19...v0.1.0-rc.21)

---
updated-dependencies:
- dependency-name: github.com/akuity/bookkeeper
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/AlecAivazis/survey/v2 v2.3.7
 	github.com/Masterminds/semver v1.5.0
 	github.com/adrg/xdg v0.4.0
-	github.com/akuity/bookkeeper v0.1.0-rc.19
+	github.com/akuity/bookkeeper v0.1.0-rc.21
 	// These important changes are merged, but not yet released:
 	// https://github.com/argoproj-labs/argocd-image-updater/pull/456
 	// https://github.com/argoproj-labs/argocd-image-updater/pull/559

go.sum

@@ -99,8 +99,8 @@ github.com/acomagu/bufpipe v1.0.4 h1:e3H4WUzM3npvo5uv95QuJM3cQspFNtFBzvJ2oNjKIDQ
 github.com/acomagu/bufpipe v1.0.4/go.mod h1:mxdxdup/WdsKVreO5GpW4+M/1CE2sMG4jeGJ2sYmHc4=
 github.com/adrg/xdg v0.4.0 h1:RzRqFcjH4nE5C6oTAxhBtoE2IRyjBSa62SCbyPidvls=
 github.com/adrg/xdg v0.4.0/go.mod h1:N6ag73EX4wyxeaoeHctc1mas01KZgsj5tYiAIwqJE/E=
-github.com/akuity/bookkeeper v0.1.0-rc.19 h1:fkKJLFN1cgLGtktzyeMPDgvkIDmXrz+Ye9F2QdJULAY=
-github.com/akuity/bookkeeper v0.1.0-rc.19/go.mod h1:L3YgPgBk9vQJmjIcbSYKz5/O725W9zpjBYKboUAGLIU=
+github.com/akuity/bookkeeper v0.1.0-rc.21 h1:VDHoS4hD1JqTlElm6Wv30XZjRnfPfQQQle//2Css6EM=
+github.com/akuity/bookkeeper v0.1.0-rc.21/go.mod h1:0+qaI12hR17Y5nfupYvdwmEv71z0H4dMgrG62zcSm1k=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=