Point to a standard license URL in POM (#663)

Using a standard license URL allows companies to automate validation of third-party library licenses. Because this library points to its own repository for the license, each company would have to manually allow-list it. For instance, Square uses https://github.com/cashapp/licensee that maintains a list of common URLs used for Apache 2.0 License: https://github.com/cashapp/licensee/blob/4ae8efb9b5a8ea34dcf35d200154e097347f1d9d/src/main/kotlin/app/cash/licensee/licenses.kt#L63-L67

gradle.properties

@@ -6,7 +6,7 @@ POM_SCM_URL=https://github.com/airbnb/mavericks
 POM_SCM_CONNECTION=scm:[email protected]:airbnb/mavericks.git
 POM_SCM_DEV_CONNECTION=scm:[email protected]:airbnb/mavericks.git
 POM_LICENSE_NAME=Apache License 2.0
-POM_LICENSE_URL=https://github.com/airbnb/mavericks/blob/main/LICENSE
+POM_LICENSE_URL=https://www.apache.org/licenses/LICENSE-2.0.txt
 POM_LICENSE_DIST=repo
 POM_DEVELOPER_ID=airbnb
 POM_DEVELOPER_NAME=Airbnb