Publishing to maven central via 'yarn maven' (#1171)

maven.sh

@@ -0,0 +1,4 @@
+version=$(git describe --tags --abbrev=0)
+url="https://www.webjars.org/deploy?webJarType=npm&nameOrUrlish=flag-icons&version=${version#v}"
+echo "curl '${url}'"
+curl "$url"

package.json

@@ -32,6 +32,7 @@
     "svgo:all": "find flags | grep '\\.svg$' | xargs -Iz -n 1 yarn svgo z && yarn ids",
     "svgo:min": "find flags | grep '\\.svg$' | xargs -Iz -n 1 svgo z && yarn ids",
     "svgo": "svgo --pretty --indent=2 --precision=1",
-    "test": "yarn prettier --list-different"
+    "test": "yarn prettier --list-different",
+    "maven": "./maven.sh"
   }
 }