feat: allow using "next" version on supported version (#58)

This also allows using the action in https://github.com/mage-os/generate-mirror-repo-js where the test module is an external package installed with composer. In this case, no local path repo configuration is needed.

Co-authored-by: Vinai Kopp <Vinai@users.noreply.github.com>

supported-version/src/nightly/get-day-before.ts

@@ -0,0 +1,8 @@
+/**
+ * Gets the date one day before the date.
+ */
+export const getDayBefore = (date: Date = new Date()) => {
+    const yesterday = new Date(date);
+    yesterday.setDate(yesterday.getDate() - 1);
+    return yesterday;
+}