Add SPDX short license identifier to all Python files

See: https://spdx.github.io/spdx-spec/appendix-V-using-SPDX-short-identifiers-in-source-files/

csv_metadata_quality/__main__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 from sys import argv
 
 from csv_metadata_quality import app

csv_metadata_quality/app.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 import argparse
 import re
 import signal

csv_metadata_quality/check.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 import os
 import re
 from datetime import datetime, timedelta

csv_metadata_quality/experimental.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 import re
 
 import langid

csv_metadata_quality/fix.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 import re
 from unicodedata import normalize
 

csv_metadata_quality/util.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 from ftfy.badness import sequence_weirdness
 
 

csv_metadata_quality/version.py

@@ -1 +1,3 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 VERSION = "0.4.8-dev"

tests/test_check.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 import pandas as pd
 from colorama import Fore
 

tests/test_fix.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 import csv_metadata_quality.fix as fix