Bump to latest RC for testing (#16)

Author: seemethere

.circleci/config.yml

@@ -117,12 +117,12 @@ workflows:
                     parameters:
                         target: ["ubuntu-16.04", "ubuntu-18.04", "centos-7", "archlinux"]
                         # Switch out to the latest RC version
-                        pytorch_ref: ["v1.7.0-rc3"]
+                        pytorch_ref: ["v1.7.0-rc4"]
                 requires:
                     - hold
             - macos_compat_build:
                 matrix:
                     parameters:
-                        pytorch_ref: ["v1.7.0-rc2"]
+                        pytorch_ref: ["v1.7.0-rc4"]
                 requires:
                     - hold