Fix nightly version name parsing

app/src/main/kotlin/org/koitharu/kotatsu/core/github/VersionId.kt

@@ -1,5 +1,6 @@
 package org.koitharu.kotatsu.core.github
 
+import org.koitharu.kotatsu.core.util.ext.digits
 import java.util.Locale
 
 data class VersionId(
@@ -48,7 +49,7 @@ fun VersionId(versionName: String): VersionId {
 		return VersionId(
 			major = 0,
 			minor = 0,
-			build = versionName.drop(1).toIntOrNull() ?: 0,
+			build = versionName.digits().toIntOrNull() ?: 0,
 			variantType = "n",
 			variantNumber = 0,
 		)

app/src/main/kotlin/org/koitharu/kotatsu/core/util/ext/String.kt

@@ -28,6 +28,8 @@ fun String.toUUIDOrNull(): UUID? = try {
 	null
 }
 
+fun String.digits() = filter { it.isDigit() }
+
 /**
  * @param threshold 0 = exact match
  */