fix pyproject.toml authors entry

pyproject.toml

@@ -5,7 +5,9 @@
 readme = "README.rst"
 requires-python = ">=3.6"
 license = {file = "LICENSE"}
-author = "XCG Consulting"
+authors = [
+  "XCG Consulting"
+]
 classifiers = [
   "Development Status :: 5 - Production/Stable",
   "Programming Language :: Python :: 3",
@@ -62,4 +64,4 @@
 depends = coverage-report
 commands =
     coverage xml
-"""
\ No newline at end of file
+"""