fix(MongoBinaryDownloadUrl): handle Debian "testing" release (#430)

Author: sktt

packages/mongodb-memory-server-core/src/util/MongoBinaryDownloadUrl.ts

@@ -192,7 +192,7 @@ export class MongoBinaryDownloadUrl {
     let name = 'debian';
     const release: number = parseFloat(os.release);
 
-    if (release >= 10 || os.release === 'unstable') {
+    if (release >= 10 || ['unstable', 'testing'].includes(os.release)) {
       name += '10';
     } else if (release >= 9) {
       name += '92';