Specify UTF-8 encoding in Python script (#808)

* Specify UTF-8 encoding in Python script

Fixes error on Windows

* Use regular open instead of io.open

Works just as well, no need for an extra import

* Fix file names

* Update update_readme.py

---------

Co-authored-by: Terence Eden <[email protected]>

update_readme.py

@@ -109,7 +109,7 @@
 readme_summary_text = f"There are currently {len(svg_list)} icons and the average size is _under_ {round(total_bytes / len(svg_list))} bytes!"
 
 #	Replace the table in README with the new one
-with open('README.md','r+') as f: 
+with open('README.md','r+', encoding="utf-8") as f: 
     file = f.read() 
 
     file = re.sub(r"(?s)<table>.*?</table>", readme_table, file)
@@ -122,7 +122,7 @@
 print(f"README.md updated with {len(svg_list)} icons.")
 
 #	Replace the tables in the REFERENCE document
-with open('REFERENCE.md','r+') as f: 
+with open('REFERENCE.md','r+', encoding="utf-8") as f: 
     file = f.read() 
 
     file = re.sub(r"(?s)-\|-\|-.*", reference_table, file)
@@ -135,7 +135,7 @@
 print(f"REFERENCE.md updated.")
 
 #	Replace the table in the CHECK document
-with open('CHECK.html','r+') as f: 
+with open('CHECK.html','r+', encoding="utf-8") as f: 
     file = f.read() 
 
     file = re.sub(r"(?s)<table>.*?</table>", check_table, file)