GODRIVER-1780 Use unstable URL for libmongocrypt Windows tests. (#534)

FLE tests require the 1.1.0-beta download, which is uploaded to a different fixed URL than the latest stable release.

Author: kevinAlbs

.evergreen/config.yml

@@ -75,7 +75,8 @@ functions:
           if [ "Windows_NT" = "$OS" ]; then
              mkdir -p c:/libmongocrypt/include
              mkdir -p c:/libmongocrypt/bin
-             curl https://s3.amazonaws.com/mciuploads/libmongocrypt/windows/latest_release/libmongocrypt.tar.gz --output libmongocrypt.tar.gz
+             # TODO: After a stable libmongocrypt 1.1.0 is released in MONGOCRYPT-293, update this URL to: https://s3.amazonaws.com/mciuploads/libmongocrypt/windows/latest_release/libmongocrypt.tar.gz
+             curl https://s3.amazonaws.com/mciuploads/libmongocrypt/windows/latest_release/libmongocrypt_unstable.tar.gz --output libmongocrypt.tar.gz
              tar -xvzf libmongocrypt.tar.gz
              cp ./bin/mongocrypt.dll c:/libmongocrypt/bin
              cp ./include/mongocrypt/*.h c:/libmongocrypt/include