ci: update ci config

Author: wfxr

.github/workflows/CICD.yml

@@ -16,14 +16,12 @@ jobs:
       fail-fast: false
       matrix:
         job:
-          # { os, target, cargo-options, features, use-cross, toolchain }
           - { os: ubuntu-latest  , target: arm-unknown-linux-gnueabihf , use-cross: use-cross }
-          - { os: ubuntu-18.04   , target: aarch64-unknown-linux-gnu   , use-cross: use-cross }
-          - { os: ubuntu-18.04   , target: i686-unknown-linux-gnu      , use-cross: use-cross }
-          - { os: ubuntu-18.04   , target: i686-unknown-linux-musl     , use-cross: use-cross }
-          - { os: ubuntu-18.04   , target: x86_64-unknown-linux-gnu    , use-cross: use-cross }
-          - { os: ubuntu-18.04   , target: x86_64-unknown-linux-musl   , use-cross: use-cross }
-          - { os: ubuntu-16.04   , target: x86_64-unknown-linux-gnu    , use-cross: use-cross }
+          - { os: ubuntu-latest  , target: aarch64-unknown-linux-gnu   , use-cross: use-cross }
+          - { os: ubuntu-latest  , target: i686-unknown-linux-gnu      , use-cross: use-cross }
+          - { os: ubuntu-latest  , target: i686-unknown-linux-musl     , use-cross: use-cross }
+          - { os: ubuntu-latest  , target: x86_64-unknown-linux-gnu    , use-cross: use-cross }
+          - { os: ubuntu-latest  , target: x86_64-unknown-linux-musl   , use-cross: use-cross }
           - { os: macos-latest   , target: x86_64-apple-darwin                                }
           # - { os: windows-latest , target: i686-pc-windows-msvc                               }
           - { os: windows-latest , target: x86_64-pc-windows-msvc                             }
@@ -41,14 +39,6 @@ jobs:
       id: vars
       shell: bash
       run: |
-        # toolchain
-        TOOLCHAIN="stable" ## default to "stable" toolchain
-        # * specify alternate TOOLCHAIN for *-pc-windows-gnu targets; gnu targets on Windows are broken for the standard *-pc-windows-msvc toolchain (refs: <https://github.com/rust-lang/rust/issues/47048>, <https://github.com/rust-lang/rust/issues/53454>, <https://github.com/rust-lang/cargo/issues/6754>)
-        case ${{ matrix.job.target }} in *-pc-windows-gnu) TOOLCHAIN="stable-${{ matrix.job.target }}" ;; esac;
-        # * use requested TOOLCHAIN if specified
-        if [ -n "${{ matrix.job.toolchain }}" ]; then TOOLCHAIN="${{ matrix.job.toolchain }}" ; fi
-        echo set-output name=TOOLCHAIN::${TOOLCHAIN}
-        echo ::set-output name=TOOLCHAIN::${TOOLCHAIN}
         # staging directory
         STAGING='_staging'
         echo set-output name=STAGING::${STAGING}