feat: add elastic license template

.editorconfig

@@ -19,3 +19,6 @@ end_of_line = lf
 indent_style = space
 insert_final_newline = true
 trim_trailing_whitespace = true
+
+[*.txt]
+insert_final_newline = false

fmt/src/license/Elastic-2.0.txt

@@ -0,0 +1,13 @@
+Copyright ${inceptionYear} ${copyrightOwner}
+
+Licensed under the Elastic 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
+
+    https://www.elastic.co/licensing/elastic-license
+
+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.

fmt/src/license/mod.rs

@@ -60,5 +60,10 @@ macro_rules! match_bundled_headers {
 }
 
 fn bundled_headers(name: &str) -> Option<HeaderSource> {
-    match_bundled_headers!(name, "Apache-2.0.txt", "Apache-2.0-ASF.txt")
+    match_bundled_headers!(
+        name,
+        "Apache-2.0.txt",
+        "Apache-2.0-ASF.txt",
+        "Elastic-2.0.txt"
+    )
 }