Update documentation and other files (#148)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

sbt-github/src/main/scala/com/alejandrohdezma/sbt/github/syntax/url.scala

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2019-2020 Alejandro Hernández <https://github.com/alejandrohdezma>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.alejandrohdezma.sbt.github.syntax
 
 import sbt.URI

sbt-github/src/test/scala/com/alejandrohdezma/sbt/github/syntax/UrlSyntaxSpec.scala

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2019-2020 Alejandro Hernández <https://github.com/alejandrohdezma>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.alejandrohdezma.sbt.github.syntax
 
 import sbt.URL