Update config.yml (#164)

* Revert the rust nightly version to the one when it used to work

* Make the docker for the develop branch as well

Author: aliX

.circleci/config.yml

@@ -13,8 +13,8 @@ commands:
             source ~/.cargo/env
             rustup install $RUST_VERSION
             rustup default $RUST_VERSION
-            rustup install nightly
-            rustup target add wasm32-unknown-unknown --toolchain=nightly
+            rustup install nightly-2020-04-17
+            rustup target add wasm32-unknown-unknown --toolchain=nightly-2020-04-17
             rustup target add x86_64-unknown-linux-musl --toolchain=$RUST_VERSION
             export RUSTC_WRAPPER="" # sccache is uninstalled at this point so it must be unset here for `wasm-gc` install
             command -v wasm-gc || cargo install --git https://github.com/alexcrichton/wasm-gc --force
@@ -143,4 +143,4 @@ workflows:
             branches:
               only:
                 - /^[0-9]+[.][0-9]+[.][0-9]+(-rc[0-9]+)*$/
-                - master
+                - develop