doc: Set different html_baseurl for stable and dev versions (#2158)

Co-authored-by: Will Schlitzer <[email protected]>

Author: seisman

doc/conf.py

@@ -137,16 +137,19 @@
 copyright = f"2017-{year}, The PyGMT Developers"  # pylint: disable=redefined-builtin
 if len(__version__.split("+")) > 1 or __version__ == "unknown":
     version = "dev"
+    # Set base_url for stable version
+    html_baseurl = "https://pygmt.org/dev/"
 else:
     version = __version__
+    # Set base_url for dev version
+    html_baseurl = "https://pygmt.org/latest/"
 release = __version__
 
 # These enable substitutions using |variable| in the rst files
 rst_epilog = f"""
 .. |year| replace:: {year}
 """
 
-html_baseurl = "https://pygmt.org/latest/"
 html_last_updated_fmt = "%b %d, %Y"
 html_title = "PyGMT"
 html_short_title = "PyGMT"