Bump pressbooks-build-tools from 0.11.0 to 0.12.0

Bumps [pressbooks-build-tools](https://github.com/pressbooks/pressbooks-build-tools) from 0.11.0 to 0.12.0.
- [Release notes](https://github.com/pressbooks/pressbooks-build-tools/releases)
- [Commits](https://github.com/pressbooks/pressbooks-build-tools/compare/0.11.0...0.12.0)

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

package.json

@@ -56,7 +56,7 @@
 		"node": ">= 6.9.4"
 	},
 	"devDependencies": {
-		"pressbooks-build-tools": "^0.11.0"
+		"pressbooks-build-tools": "^0.12.0"
 	},
 	"dependencies": {
 		"aetna": "^1.0.0-alpha.17",