Bump github.com/signintech/gopdf from 0.27.1 to 0.28.0 (#24)

Bumps [github.com/signintech/gopdf](https://github.com/signintech/gopdf) from 0.27.1 to 0.28.0.
- [Changelog](https://github.com/signintech/gopdf/blob/master/Changelog.md)
- [Commits](signintech/gopdf@v0.27.1...v0.28.0)

---
updated-dependencies:
- dependency-name: github.com/signintech/gopdf
  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 1.23.1
 
 require (
 	github.com/joho/godotenv v1.5.1
-	github.com/signintech/gopdf v0.27.1
+	github.com/signintech/gopdf v0.28.0
 	github.com/unidoc/unioffice v1.36.0
 )
 

go.sum

@@ -6,7 +6,7 @@ github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/richardlehane/msoleps v1.0.3 h1:aznSZzrwYRl3rLKRT3gUk9am7T/mLNSnJINvN0AQoVM=
 github.com/richardlehane/msoleps v1.0.3/go.mod h1:BWev5JBpU9Ko2WAgmZEuiz4/u3ZYTKbjLycmwiWUfWg=
-github.com/signintech/gopdf v0.27.1 h1:e3hKauvFbKoIk2jz4HaUsnwuEzsN1xJOFag6ZR6JbFY=
-github.com/signintech/gopdf v0.27.1/go.mod h1:d23eO35GpEliSrF22eJ4bsM3wVeQJTjXTHq5x5qGKjA=
+github.com/signintech/gopdf v0.28.0 h1:zCUlRuedALiKaZmEdLSoA4EPqjpnzLBP6co8fjA6C7Q=
+github.com/signintech/gopdf v0.28.0/go.mod h1:d23eO35GpEliSrF22eJ4bsM3wVeQJTjXTHq5x5qGKjA=
 github.com/unidoc/unioffice v1.36.0 h1:9kEUK3hQhVAB7g3lROsvCrSMZsxSwFmC1UiMox7RohQ=
 github.com/unidoc/unioffice v1.36.0/go.mod h1:VL/S9i/xd2zYqZCUzO6CFPr3kM4iKj/tLcEcthAilgU=