(core) update fly.yml to use 0.1.66 version of flyctl and to use V2 of flydev (so no scaling of Nomad)

Test Plan: manually run github action on github to check if applciation is deploying and destroing afterwards

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D3983

buildtools/fly-template.toml

@@ -1,4 +1,5 @@
 app = "{APP_NAME}"
+primary_region = "ewr"
 kill_signal = "SIGINT"
 kill_timeout = 5
 processes = []