azure: use apt-get instead of apt-fast

From
nim-lang#17325 (comment), it
appears that apt-fast is ignoring errors.

azure-pipelines.yml

@@ -64,9 +64,9 @@ jobs:
       displayName: 'Install node.js 12.x'
 
     - bash: |
-        sudo apt-fast update -qq
+        sudo apt-get update -qq
         DEBIAN_FRONTEND='noninteractive' \
-          sudo apt-fast install --no-install-recommends -yq \
+          sudo apt-get install --no-install-recommends -yq \
             libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev valgrind libc6-dbg
       displayName: 'Install dependencies (amd64 Linux)'
       condition: and(eq(variables['Agent.OS'], 'Linux'), eq(variables['CPU'], 'amd64'))
@@ -82,11 +82,11 @@ jobs:
         Pin-Priority: 1001
         EOF
 
-        sudo apt-fast update -qq
+        sudo apt-get update -qq
         # `:i386` (e.g. in `libffi-dev:i386`) is needed otherwise you may get:
         # `could not load: libffi.so` during dynamic loading.
         DEBIAN_FRONTEND='noninteractive' \
-          sudo apt-fast install --no-install-recommends --allow-downgrades -yq \
+          sudo apt-get install --no-install-recommends --allow-downgrades -yq \
             g++-multilib gcc-multilib libcurl4-openssl-dev:i386 libgc-dev:i386 \
             libsdl1.2-dev:i386 libsfml-dev:i386 libglib2.0-dev:i386 libffi-dev:i386