Bump pressbooks-build-tools from 1.1.0 to 1.2.0

Bumps [pressbooks-build-tools](https://github.com/pressbooks/pressbooks-build-tools) from 1.1.0 to 1.2.0.
- [Release notes](https://github.com/pressbooks/pressbooks-build-tools/releases)
- [Commits](https://github.com/pressbooks/pressbooks-build-tools/compare/1.1.0...1.2.0)

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

package.json

@@ -60,7 +60,7 @@
 		"node": ">= 6.9.4"
 	},
 	"devDependencies": {
-		"pressbooks-build-tools": "^1.1.0",
+		"pressbooks-build-tools": "^1.2.0",
 		"sass": "^1.15.2",
 		"sass-loader": "^7.1.0",
 		"vue-template-compiler": "^2.5.21"