feat: widen webpack peer support

Agent-Logs-Url: https://github.com/TypeStrong/ts-loader/sessions/74b74f2d-76ad-4022-9635-77d0c5acce76

Co-authored-by: johnnyreilly <1010525+johnnyreilly@users.noreply.github.com>

Author: Copilot

README.md

@@ -133,10 +133,10 @@ If you'd like to see a simple setup take a look at [our example](examples/fork-t
 ### Compatibility
 
 * TypeScript: 3.6.3+
-* webpack: 5.x+ (please use `ts-loader` 8.x if you need webpack 4 support)
+* webpack: 4.x+ and 5.x+
 * node: 12.x+
 
-A full test suite runs each night (and on each pull request). It runs both on Linux and Windows, testing `ts-loader` against major releases of TypeScript. The test suite also runs against TypeScript@next (because we want to use it as much as you do).
+A full test suite runs each night (and on each pull request). It runs both on Linux and Windows, testing `ts-loader` against major releases of TypeScript. Execution tests continue to run against webpack 5 in CI, and the test suite also runs against TypeScript@next (because we want to use it as much as you do).
 
 If you become aware of issues not caught by the test suite then please let us know. Better yet, write a test and submit it in a PR!
 

package.json

@@ -99,7 +99,7 @@
   },
   "peerDependencies": {
     "typescript": "*",
-    "webpack": "^5.0.0"
+    "webpack": "^4.0.0 || ^5.0.0"
   },
   "publishConfig": {
     "provenance": true