[Infra] Ignore release_report.md from formatter

The file is auto generated and not intended to be consumed directly,
thus formatting isn't a priority. Also, since it's generated during
the release process, the only way of running the formatter would be
checking out the branch, which is not necessary for any other step of
the process.

Author: rlazo

build.gradle.kts

@@ -62,7 +62,7 @@ fun Project.applySpotless() {
     }
     format("styling") {
       target("src/**/*.md", "*.md", "docs/**/*.md")
-      targetExclude("**/third_party/**", "src/test/resources/**")
+      targetExclude("**/third_party/**", "src/test/resources/**", "release_report.md")
       prettier().config(mapOf("printWidth" to 100, "proseWrap" to "always"))
     }
   }