go.mod: bump google.golang.org/grpc from 1.67.1 to 1.68.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.67.1 to 1.68.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](grpc/grpc-go@v1.67.1...v1.68.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -19,7 +19,7 @@ require (
 	golang.org/x/sync v0.8.0
 	golang.org/x/time v0.7.0
 	golang.org/x/tools v0.26.0
-	google.golang.org/grpc v1.67.1
+	google.golang.org/grpc v1.68.0
 	gopkg.in/tomb.v2 v2.0.0-20161208151619-d5d1b5820637
 	mvdan.cc/gofumpt v0.7.0
 )

go.sum

@@ -623,8 +623,8 @@ golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20240930140551-af27646dc61f h1:cUMEy+8oS78BWIH9OWazBkzbr090Od9tWBNtZHkOhf0=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20240930140551-af27646dc61f/go.mod h1:UqMtugtsSgubUsoxbuAoiCXvqvErP7Gf0so0mK9tHxU=
-google.golang.org/grpc v1.67.1 h1:zWnc1Vrcno+lHZCOofnIMvycFcc0QRGIzm9dhnDX68E=
-google.golang.org/grpc v1.67.1/go.mod h1:1gLDyUQU7CTLJI90u3nXZ9ekeghjeM7pTDZlqFNg2AA=
+google.golang.org/grpc v1.68.0 h1:aHQeeJbo8zAkAa3pRzrVjZlbz6uSfeOXlJNQM0RAbz0=
+google.golang.org/grpc v1.68.0/go.mod h1:fmSPC5AsjSBCK54MyHRx48kpOti1/jRfOlwEWywNjWA=
 google.golang.org/protobuf v1.35.1 h1:m3LfL6/Ca+fqnjnlqQXNpFPABW1UD7mjh8KO2mKFytA=
 google.golang.org/protobuf v1.35.1/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=