Fix the Issues query string and update version

While eclipse/xtext redirects to eclipse-xtext/xtext when browsing, it
is required to explicitly search within the latter, otherwise no results
show up.

README.md

@@ -12,7 +12,7 @@ More information can be found on https://eclipse.dev/Xtext/.
 - [All Open Issues](https://github.com/search?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+repo%3Aeclipse%2Fxtext+repo%3Aeclipse%2Fxtext-website&type=issues&ref=searchresultsopen+repo%3Aeclipse%2Fxtext+repo%3Aeclipse%2Fxtext-website)
 - [Good First Issues](https://github.com/search?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+repo%3Aeclipse%2Fxtext+repo%3Aeclipse%2Fxtext-website+label%3A%22good+first+issue%22&type=issues)
 
-- [All Open Issues of Milestone Release_2.36](https://github.com/search?utf8=%E2%9C%93&q=is%3Aissue+milestone%3ARelease_2.36+is%3Aopen+repo%3Aeclipse%2Fxtext+repo%3Aeclipse%2Fxtext-website&type=issues)
+- [All Open Issues of Milestone Release_2.38](https://github.com/search?utf8=%E2%9C%93&q=is%3Aissue+milestone%3ARelease_2.38+is%3Aopen+repo%3Aeclipse-xtext%2Fxtext+repo%3Aeclipse-xtext%2Fxtext-website&type=issues)
 
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