add support for Repos with Numbers in their name (#255)

* add support for Repos with Numbers in their name

* Update strings_sy.xml

changed invalid_repo_name to better reflect its meaning

app/src/main/java/eu/kanade/tachiyomi/ui/category/repos/RepoPresenter.kt

@@ -79,6 +79,6 @@ class RepoPresenter(
     }
 
     companion object {
-        val repoRegex = """^[a-zA-Z-_.]*?\/[a-zA-Z-_.]*?$""".toRegex()
+        val repoRegex = """^[a-zA-Z0-9-_.]*?\/[a-zA-Z0-9-_.]*?$""".toRegex()
     }
 }