Bump to the latest rust buildpack

jtgeibel · jtgeibel · commit ec656a172ace · 2020-09-20T11:53:29.000-04:00
emk/heroku-buildpack-rust@578d630...cfa0f06
diff --git a/.buildpacks b/.buildpacks
@@ -1,4 +1,4 @@
-https://github.com/emk/heroku-buildpack-rust#578d630
+https://github.com/emk/heroku-buildpack-rust#cfa0f06
 https://github.com/heroku/heroku-buildpack-nodejs#v176
 https://github.com/heroku/heroku-buildpack-nginx.git#fbc49cd
 https://github.com/sgrif/heroku-buildpack-diesel#f605edd
