Fix cache keys for Python version ranges (#937)

## Summary
- URL-encode the Python version component before adding it to the cache
key
- URL-encode the user-provided cache suffix for the same reason
- Add cache key tests for Python ranges, comma-containing suffixes, and
unchanged simple inputs

Fixes #914

Refs: pi-session 019f3164-85e7-7817-bffd-501d89b3a1fd

## Tests
- npm run all

src/cache/restore-cache.ts

@@ -94,8 +94,10 @@ async function computeKeys(
   if (cacheDependencyPathHash === "-") {
     cacheDependencyPathHash = "-no-dependency-glob";
   }
-  const suffix = inputs.cacheSuffix ? `-${inputs.cacheSuffix}` : "";
-  const version = pythonVersion ?? "unknown";
+  const suffix = inputs.cacheSuffix
+    ? `-${encodeURIComponent(inputs.cacheSuffix)}`
+    : "";
+  const version = encodeURIComponent(pythonVersion ?? "unknown");
   const platform = await getPlatform();
   const osNameVersion = getOSNameVersion();
   const pruned = inputs.pruneCache ? "-pruned" : "";