Update version number to v1.3.0

Author: avalentino

docs/NEWS.rst

@@ -2,7 +2,7 @@ Change history
 ==============
 
 
-PyEPR 1.3.0 (UNRELEASED)
+PyEPR 1.3.0 (03/01/2026)
 ------------------------
 
 * Update the bundled epr-api library source code to v2.3.

docs/index.rst

@@ -77,6 +77,7 @@ ENVISAT Product Reader Python API
 
     ============ ======================================================
     PyEPR latest https://pyepr.readthedocs.io/en/latest (development)
+    PyEPR 1.3.0  https://pyepr.readthedocs.io/en/v1.3.0
     PyEPR 1.2.0  https://pyepr.readthedocs.io/en/v1.2.0
     PyEPR 1.1.5  https://pyepr.readthedocs.io/en/v1.1.5
     PyEPR 1.1.4  https://pyepr.readthedocs.io/en/v1.1.4