[STYLE] possible regression fix by using char-class (- WIP #485 -)

Changes in file .github/actions/check-control/action.yml:
 * minor refactor

Changes in file .github/actions/run-minimal-acceptance-tests/action.yml:
 * minor refactor

Changes in file .github/actions/setup-py-reqs/action.yml:
 * minor refactor

Author: reactive-firewall

.github/actions/check-control/action.yml

@@ -115,7 +115,7 @@ runs:
         raw_input='${{ inputs.sha }}'
 
         # Reject NUL or newline immediately
-        if printf '%s' "$raw_input" | grep -q $'[\\x00\\n\\r]'; then
+        if printf '%s' "$raw_input" | grep -q '[^[:print:]]'; then
           printf "::error title='Invalid':: %s\n" "Error: input contains disallowed control characters" >&2
           exit 1
         fi

.github/actions/run-minimal-acceptance-tests/action.yml

@@ -88,7 +88,7 @@ runs:
         raw_input='${{ inputs.sha }}'
 
         # Reject NUL or newline immediately
-        if printf '%s' "$raw_input" | grep -q $'[\\x00\\n\\r]'; then
+        if printf '%s' "$raw_input" | grep -q '[^[:print:]]'; then
           printf "::error title='Invalid':: %s\n" "Error: input contains disallowed control characters" >&2
           exit 1
         fi

.github/actions/setup-py-reqs/action.yml

@@ -73,7 +73,7 @@ runs:
         raw_input='${{ inputs.sha }}'
 
         # Reject NUL or newline immediately
-        if printf '%s' "$raw_input" | grep -q $'[\\x00\\n\\r]'; then
+        if printf '%s' "$raw_input" | grep -q '[^[:print:]]'; then
           printf "::error title='Invalid':: %s\n" "Error: input contains disallowed control characters" >&2
           exit 1
         fi