Merge branch 'main' into release/v2

* main:
  Prepare for release 2.11.1.
  Update npm packages.
  Bump @actions/core from 1.2.4 to 1.2.6
  Update to gradle 6.7-rc-1 for test fixture. Build with Java 15 on CI.
  Improve GitHub Actions Gradle cache.
  Add square/radiography to adopter list
  Add cashapp/copper to adapter list
  SDK Build tools 30.0.2.
  Update fixture dependencies.
  Gradle 6.6.
  Update README.md
  Update packages.
  Build tools 30.0.1.
  Use fs for writing licence files.
  Update cmdline-tools to 2.1.

node_modules/@actions/tool-cache/lib/manifest.d.ts

@@ -0,0 +1,16 @@
+export interface IToolReleaseFile {
+    filename: string;
+    platform: string;
+    platform_version?: string;
+    arch: string;
+    download_url: string;
+}
+export interface IToolRelease {
+    version: string;
+    stable: boolean;
+    release_url: string;
+    files: IToolReleaseFile[];
+}
+export declare function _findMatch(versionSpec: string, stable: boolean, candidates: IToolRelease[], archFilter: string): Promise<IToolRelease | undefined>;
+export declare function _getOsVersion(): string;
+export declare function _readLinuxVersionFile(): string;