Bump fortio.org/log from 1.7.0 to 1.8.1 (#87)

Bumps [fortio.org/log](https://github.com/fortio/log) from 1.7.0 to 1.8.1.
- [Release notes](https://github.com/fortio/log/releases)
- [Commits](fortio/log@v1.7.0...v1.8.1)

---
updated-dependencies:
- dependency-name: fortio.org/log
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

go.mod

@@ -4,7 +4,7 @@ go 1.18
 
 require (
 	fortio.org/cli v1.2.0
-	fortio.org/log v1.7.0
+	fortio.org/log v1.8.1
 	fortio.org/testscript v0.3.1
 	fortio.org/version v1.0.2
 )

go.sum

@@ -1,7 +1,7 @@
 fortio.org/cli v1.2.0 h1:MXmbYnbNHcclf0xYLZjeCnTINby7FpooJxR01+hnBmM=
 fortio.org/cli v1.2.0/go.mod h1:zJwHjRnvVqneF7ES+REfElc33xMjhbRDJslSrqIK9Kk=
-fortio.org/log v1.7.0 h1:4MbU81zqe/3RYuHpXADNgJwd2KEMAwmMUtuF5qtZTug=
-fortio.org/log v1.7.0/go.mod h1:u/8/2lyczXq52aT5Nw6reD+3cR6m/EbS2jBiIYhgiTU=
+fortio.org/log v1.8.1 h1:Ybtjp+qDXb124ESnZ0XVuXJ6khDrWcom/C55YPupoKg=
+fortio.org/log v1.8.1/go.mod h1:u/8/2lyczXq52aT5Nw6reD+3cR6m/EbS2jBiIYhgiTU=
 fortio.org/testscript v0.3.1 h1:MmRO64AsmzaU1KlYMzAbotJIMKRGxD1XXssJnBRiMGQ=
 fortio.org/testscript v0.3.1/go.mod h1:7OJ+U4avooRNqc7p/VHKJadYgj9fA6+N0SbGU8FVWGs=
 fortio.org/version v1.0.2 h1:8NwxdX58aoeKx7T5xAPO0xlUu1Hpk42nRz5s6e6eKZ0=