Use Azure storage SDK to download cache (#497)

* Adds option to download using AzCopy

* Bump version number and add release notes

* Ensure we use at least v10

* Negate env var so it disables AzCopy

* Use Azure storage SDK to download cache

* Use same level of parallelism as AzCopy

* Fix naming of variable

* React to feedback

* Bump Node types to Node 12

* Make linter happy

* Pass options into restoreCache method

* Fix tests

* Restructure files and add tests

* Add method to get the default download and upload options

* Include breaking changes in RELEASES.md

Co-authored-by: Josh Gross <joshmgross@github.com>

src/internal/cacheUtils.ts

@@ -113,3 +113,11 @@ export async function isGnuTarInstalled(): Promise<boolean> {
   const versionOutput = await getVersion('tar')
   return versionOutput.toLowerCase().includes('gnu tar')
 }
+
+export function assertDefined<T>(name: string, value?: T): T {
+  if (value === undefined) {
+    throw Error(`Expected ${name} but value was undefiend`)
+  }
+
+  return value
+}