Trivial: Add dub.selections.json to gitignore

Geod24 · Geod24 · commit eb99121cd0ec · 2022-06-02T11:30:38.000+02:00
Because dub test generates it, but library usually don't commit it.
diff --git a/.gitignore b/.gitignore
@@ -5,6 +5,7 @@
 /.dub/
 /openssl
 /*-test-library
+dub.selections.json
 
 /examples/sslecho/sslecho
 /examples/sslecho/test
