Download precompiled cargo-make in CI.

Newer versions of `cargo-make` drop support for rust 1.21.0. We
still support 1.21.0, so we'll used a precompiled binary
in CI until we drop support for 1.21.0.

Fixes https://github.com/graphql-rust/juniper/issues/191

.travis.yml

@@ -18,7 +18,9 @@ env:
     - CARGO_MAKE_RUN_CODECOV=true
 
 script:
-  - cargo install -f --debug cargo-make
+  - mkdir -p ~/.cargo/bin
+  - "curl -L https://bintray.com/sagiegurari/cargo-make/download_file?file_path=cargo-make_v0.11.0 -o ~/.cargo/bin/cargo-make"
+  - chmod +x ~/.cargo/bin/cargo-make
   - cargo make workspace-ci-flow --no-workspace
 
 before_deploy:

appveyor.yml

@@ -30,7 +30,6 @@ install:
   - cargo -V
   - cargo install --debug cargo-make
 
-
 # 'cargo test' takes care of building for us, so disable Appveyor's build stage. This prevents
 # the "directory does not contain a project or solution file" error.
 # source: https://github.com/starkat99/appveyor-rust/blob/master/appveyor.yml#L113
@@ -38,4 +37,3 @@ build: false
 
 test_script:
    - cargo make workspace-ci-flow --no-workspace
-