Deprecate old ignore file (HunterMcGushion#87)

Author: MiWeiss

README.md

@@ -142,8 +142,10 @@ docstr-coverage docstr_coverage -e ".*/test" --skip-magic --skip-init --badge="d
 
 Note that options passed as command line arguments have precedence over options 
 configured in a config file.
-Exception: If a (deprecated) `--docstr-ignore-file` is present and the yml config contains `ignore_patterns`,
-a `ValueError` is raised.
+
+#### Ignoring by Regex
+In your config files, using `ignore_patterns`, you can specify regex patterns for files names and nodes (methods, ...)
+which should be ignored. See config file example above.
 
 #### Overriding by Comments
 Note that `docstr-coverage` can not parse 

docstr_coverage/cli.py

@@ -301,7 +301,7 @@ def execute(paths, **kwargs):
         raise ValueError(
             (
                 "The docstr-coverage configuration file {} contains ignore_patterns,"
-                " and at the same time an ignore file {} was found."
+                " and at the same time a (deprecated) ignore file {} was found."
                 " Ignore patterns must be specified in only one location at a time."
             ).format(kwargs["config_file"], kwargs["ignore_names_file"])
         )
@@ -369,7 +369,19 @@ def _deprecation_alerts(kwargs):
                 "Using deprecated --{}, should use --{}".format(deprecated_name, new_flag), fg="red"
             )
             kwargs[name] = kwargs.pop(deprecated_name)
-    if kwargs.get("docstr-ignore-file") or kwargs.get("ignore_names_file"):
+
+    # Deprecated old ignore files
+    ignore_file_old_casing = kwargs.get("docstr-ignore-file")
+    ignore_file_new_casing = kwargs.get("ignore_names_file")
+
+    def _nondefault_or_existing_file(path):
+        if path is None:
+            return False
+        return os.path.split(path)[-1] != ".docstr_coverage" or os.path.isfile(path)
+
+    if _nondefault_or_existing_file(ignore_file_old_casing) or _nondefault_or_existing_file(
+        ignore_file_new_casing
+    ):
         click.secho(
             "Using deprecated ignore files."
             "We'll keep them supported for a while, "