Run clippy from the test script

Currently we run clippy in CI using a github action. The invocation has
a couple of shortcomings

1. it does not lint the tests (this requires `--all-targets`)
2. it does not lint the examples

I could not find a way to lint the examples without explicitly linting
each example by name.

Move the clippy control to `test.sh` and add an env var `DO_LINT` to
control it. Remove the explicit CI job and run the linter during the
`Test` job using the stable toolchain.

.github/workflows/rust.yml

@@ -13,6 +13,7 @@ jobs:
           - rust: stable
             env:
               DO_COV: true
+              DO_LINT: true
               AS_DEPENDENCY: true
               DO_NO_STD: true
           - rust: beta
@@ -106,19 +107,3 @@ jobs:
           RUSTFLAGS: "-C link-arg=-Tlink.x"
           CARGO_TARGET_THUMBV7M_NONE_EABI_RUNNER: "qemu-system-arm -cpu cortex-m3 -machine mps2-an385 -nographic -semihosting-config enable=on,target=native -kernel"
         run: cd embedded && cargo run --target thumbv7m-none-eabi
-
-  Clippy:
-    name: Clippy
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-      - run: rustup component add clippy
-      - uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --all-features -- -D warnings

contrib/test.sh

@@ -31,6 +31,14 @@ if [ "$duplicate_dependencies" -ne 0 ]; then
     exit 1
 fi
 
+if [ "$DO_LINT" = true ]
+then
+    cargo clippy --all-features --all-targets -- -D warnings
+    cargo clippy --example bip32 -- -D warnings
+    cargo clippy --example handshake -- -D warnings
+    cargo clippy --example ecdsa-psbt --features=bitcoinconsensus -- -D warnings
+fi
+
 echo "********* Testing std *************"
 # Test without any features other than std first
 cargo test --verbose --no-default-features --features="std"