Use Ubuntu 18.04 LTS and default Rust instead of rustup

Author: termoshtt

azure-pipelines.yml

@@ -1,63 +1,35 @@
 jobs:
   - job: LinuxOpenBLAS
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
     steps:
-      - script: |
-          curl -sSf https://sh.rustup.rs | sh -s -- -y
-          echo "##vso[task.setvariable variable=PATH;]$PATH:$HOME/.cargo/bin"
-        displayName: install rustup
-      - script: |
-          sudo apt-get update
-          sudo apt-get install -y gfortran
-        displayName: apt install
       - script: |
           cargo test -v --features=openblas --no-default-features
           cargo test -v --features=openblas,serde-1 --no-default-features
         displayName: run test
 
   - job: LinuxStaticOpenBLAS
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
     steps:
-      - script: |
-          curl -sSf https://sh.rustup.rs | sh -s -- -y
-          echo "##vso[task.setvariable variable=PATH;]$PATH:$HOME/.cargo/bin"
-        displayName: install rustup
-      - script: |
-          sudo apt-get update
-          sudo apt-get install -y gfortran
-        displayName: apt install
       - script: |
           cargo test -v --features=openblas-static --no-default-features
           cargo test -v --features=openblas-static,serde-1 --no-default-features
         displayName: run test
 
   - job: LinuxNetlib
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
     steps:
-      - script: |
-          curl -sSf https://sh.rustup.rs | sh -s -- -y
-          echo "##vso[task.setvariable variable=PATH;]$PATH:$HOME/.cargo/bin"
-        displayName: install rustup
-      - script: |
-          sudo apt-get update
-          sudo apt-get install -y cmake gfortran
-        displayName: apt install
       - script: |
           cargo test -v --features=netlib --no-default-features
           cargo test -v --features=netlib,serde-1 --no-default-features
         displayName: run test
 
   - job: LinuxIntelMKL
     pool:
-      vmImage: 'ubuntu-16.04'
+      vmImage: 'ubuntu-18.04'
     steps:
-      - script: |
-          curl -sSf https://sh.rustup.rs | sh -s -- -y
-          echo "##vso[task.setvariable variable=PATH;]$PATH:$HOME/.cargo/bin"
-        displayName: install rustup
       - script: |
           cargo test -v --features=intel-mkl --no-default-features
           cargo test -v --features=intel-mkl,serde-1 --no-default-features