Use conservative env var brace wrapping in "Check License" workflow

Even if it works as intended, it is not clear what the effect is of the escaped quote at the end of the environment
variables in the shell commands used to check the license detection results. Wrapping the variable names in braces
ensures they are as expected and also makes the working of the code clear.

Author: per1234

.github/workflows/check-license.yml

@@ -51,14 +51,14 @@ jobs:
 
           DETECTED_LICENSE_FILE="$(echo "$LICENSEE_OUTPUT" | jq .matched_files[0].filename | tr --delete '\r')"
           echo "Detected license file: $DETECTED_LICENSE_FILE"
-          if [ "$DETECTED_LICENSE_FILE" != "\"$EXPECTED_LICENSE_FILENAME\"" ]; then
+          if [ "$DETECTED_LICENSE_FILE" != "\"${EXPECTED_LICENSE_FILENAME}\"" ]; then
             echo "ERROR: detected license file doesn't match expected: $EXPECTED_LICENSE_FILENAME"
             EXIT_STATUS=1
           fi
 
           DETECTED_LICENSE_TYPE="$(echo "$LICENSEE_OUTPUT" | jq .matched_files[0].matched_license | tr --delete '\r')"
           echo "Detected license type: $DETECTED_LICENSE_TYPE"
-          if [ "$DETECTED_LICENSE_TYPE" != "\"$EXPECTED_LICENSE_TYPE\"" ]; then
+          if [ "$DETECTED_LICENSE_TYPE" != "\"${EXPECTED_LICENSE_TYPE}\"" ]; then
             echo "ERROR: detected license type doesn't match expected $EXPECTED_LICENSE_TYPE"
             EXIT_STATUS=1
           fi