Downgrade wdio-mediawiki to v3 and bump version to 6.3.0

According to discussion on Phabricator (specifically T406844#11284701),
we should first upgrade to wdio-mediawiki v3 and update Wikibase to
WebdriverIO v8; then wdio-mediawiki v4 with WebdriverIO v9; and only
then wdio-mediawiki v5 with ECMAScript modules.

Bump the version in the same commit so that we can release this quickly.
I’m skipping version 6.2 because I think making our minor version match
the wdio-mediawiki major version (only until we’re done with this
upgrade) should be a useful mnemonic.

Bug: T406844

Author: lucaswerkmeister

package-lock.json

@@ -1,6 +1,6 @@
 {
 	"name": "wdio-wikibase",
-	"version": "6.1.0",
+	"version": "6.3.0",
 	"description": "WebdriverIO plugin for testing a Wikibase repo.",
 	"homepage": "https://github.com/wmde/wdio-wikibase",
 	"bugs": "https://phabricator.wikimedia.org/",
@@ -22,7 +22,7 @@
 	},
 	"peerDependencies": {
 		"mwbot": "^2.0.0",
-		"wdio-mediawiki": "^5.1.0",
+		"wdio-mediawiki": "^3.0.1",
 		"webdriverio": "^7.0 || ^8.16 || ^9"
 	},
 	"devDependencies": {