Merge pull request #154 from usabilla/add-alpine3.12

Add Alpine 3.12

Author: WyriHaximus

Makefile

@@ -26,6 +26,7 @@ build-cli: clean-tags
 	./build-php.sh cli 7.3 3.11
 	./build-php.sh cli 7.4 3.10
 	./build-php.sh cli 7.4 3.11
+	./build-php.sh cli 7.4 3.12
 
 build-fpm: BUILDINGIMAGE=fpm
 build-fpm: clean-tags
@@ -39,6 +40,7 @@ build-fpm: clean-tags
 	./build-php.sh fpm 7.3 3.11
 	./build-php.sh fpm 7.4 3.10
 	./build-php.sh fpm 7.4 3.11
+	./build-php.sh fpm 7.4 3.12
 
 # Docker HTTP images build matrix ./build-nginx.sh (nginx version) (extra tag)
 build-http: BUILDINGIMAGE=http