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>

packages/cache/__tests__/options.test.ts

@@ -0,0 +1,54 @@
+import {
+  DownloadOptions,
+  UploadOptions,
+  getDownloadOptions,
+  getUploadOptions
+} from '../src/options'
+
+const useAzureSdk = true
+const downloadConcurrency = 8
+const timeoutInMs = 30000
+const uploadConcurrency = 4
+const uploadChunkSize = 32 * 1024 * 1024
+
+test('getDownloadOptions sets defaults', async () => {
+  const actualOptions = getDownloadOptions()
+
+  expect(actualOptions).toEqual({
+    useAzureSdk,
+    downloadConcurrency,
+    timeoutInMs
+  })
+})
+
+test('getDownloadOptions overrides all settings', async () => {
+  const expectedOptions: DownloadOptions = {
+    useAzureSdk: false,
+    downloadConcurrency: 14,
+    timeoutInMs: 20000
+  }
+
+  const actualOptions = getDownloadOptions(expectedOptions)
+
+  expect(actualOptions).toEqual(expectedOptions)
+})
+
+test('getUploadOptions sets defaults', async () => {
+  const actualOptions = getUploadOptions()
+
+  expect(actualOptions).toEqual({
+    uploadConcurrency,
+    uploadChunkSize
+  })
+})
+
+test('getUploadOptions overrides all settings', async () => {
+  const expectedOptions: UploadOptions = {
+    uploadConcurrency: 2,
+    uploadChunkSize: 16 * 1024 * 1024
+  }
+
+  const actualOptions = getUploadOptions(expectedOptions)
+
+  expect(actualOptions).toEqual(expectedOptions)
+})