Get and use latest shellcheck for tests

Now we use shellcheck 0.7.0 on Ubuntu hosts for test, but also use 0.7.2 or
later on macOS host via brew. So, not specifying version and always fetch & run
latest version of shellcheck on Ubuntu host is better.

We don't have a reason to stick to 0.7.0, IMHO.

Author: h-yamane-sti

.github/workflows/main.yml

@@ -14,9 +14,9 @@ jobs:
       run: |
         sudo apt-get update -y
         sudo apt-get install -y devscripts debhelper moreutils fakeroot jq pigz
-        wget "https://github.com/koalaman/shellcheck/releases/download/v0.7.0/shellcheck-v0.7.0.linux.x86_64.tar.xz"
-        tar --xz -xvf "shellcheck-v0.7.0.linux.x86_64.tar.xz"
-        sudo cp shellcheck-v0.7.0/shellcheck /usr/bin/shellcheck
+        wget "https://github.com/koalaman/shellcheck/releases/download/latest/shellcheck-latest.linux.x86_64.tar.xz"
+        tar --xz -xvf "shellcheck-latest.linux.x86_64.tar.xz"
+        sudo cp shellcheck-latest/shellcheck /usr/bin/shellcheck
       if: matrix.os != 'macos-latest'
     - name: Install Dependencies (macOS)
       run: |

test/test-shellcheck.sh

@@ -9,10 +9,10 @@ BASE_PATH=$(cd "$(dirname "$0")/../" && pwd)
 begin_test "shellcheck: reports no errors or warnings"
 (
   set -e
-  # We manually install Shellcheck 0.7.0 on Linux builds as other options
+  # We manually install the latest Shellcheck on Linux builds as other options
   # are too old.
-  if [ -x "$BASE_PATH/shellcheck-v0.7.0/shellcheck" ]; then
-    shellcheck() { "$BASE_PATH/shellcheck-v0.7.0/shellcheck" "$@"; }
+  if [ -x "$BASE_PATH/shellcheck-latest/shellcheck" ]; then
+    shellcheck() { "$BASE_PATH/shellcheck-latest/shellcheck" "$@"; }
   fi
 
   if ! type shellcheck 1>/dev/null 2>&1; then