maintainers: create sage team

Maintaining all the packages whose updates might break some aspect of
sage.

For reference:
https://github.com/NixOS/nixpkgs/pull/103810#issuecomment-727536510

pkgs/applications/science/math/sage/flask-oldsessions.nix

@@ -30,7 +30,7 @@ buildPythonPackage rec {
   meta = with stdenv.lib; {
     description = "Provides a session class that works like the one in Flask before 0.10.";
     license = licenses.bsd2;
-    maintainers = with maintainers; [ timokau ];
+    maintainers = teams.sage.members;
     homepage = "https://github.com/mitsuhiko/flask-oldsessions";
   };
 }

pkgs/applications/science/math/sage/flask-openid.nix

@@ -22,7 +22,7 @@ buildPythonPackage rec {
   meta = with stdenv.lib; {
     description = "Adds openid support to flask applications";
     license = licenses.bsd2;
-    maintainers = with maintainers; [ timokau ];
+    maintainers = teams.sage.members;
     homepage = "https://pythonhosted.org/Flask-OpenID/";
   };
 }

pkgs/applications/science/math/sage/pybrial.nix

@@ -20,6 +20,6 @@ buildPythonPackage rec {
     meta = with stdenv.lib; {
       description = "python implementation of BRiAl";
       license = licenses.gpl2;
-      maintainers = with maintainers; [ timokau ];
+      maintainers = teams.sage.members;
     };
 }

pkgs/applications/science/math/sage/python-openid.nix

@@ -34,7 +34,7 @@ buildPythonPackage rec {
   meta = with stdenv.lib; {
     description = "OpenID library for Python";
     license = licenses.asl20;
-    maintainers = with maintainers; [ timokau ];
+    maintainers = teams.sage.members;
     homepage = "https://github.com/openid/python-openid/";
   };
 }

pkgs/applications/science/math/sage/sage.nix

@@ -63,6 +63,6 @@ stdenv.mkDerivation rec {
   meta = with stdenv.lib; {
     description = "Open Source Mathematics Software, free alternative to Magma, Maple, Mathematica, and Matlab";
     license = licenses.gpl2;
-    maintainers = with maintainers; [ timokau ];
+    maintainers = teams.sage.members;
   };
 }

pkgs/applications/science/math/sage/sagenb.nix

@@ -46,7 +46,7 @@ buildPythonPackage rec {
   meta = with stdenv.lib; {
     description = "Sage Notebook";
     license = licenses.gpl3Plus;
-    maintainers = with maintainers; [ timokau ];
+    maintainers = teams.sage.members;
   };
 
   # let sagenb use mathjax