update mailmap and CITATION.cff for 6.2

.mailmap

@@ -68,3 +68,5 @@ Sam D Porter <92305641+samdporter@users.noreply.github.com>
 Sam D Porter <92305641+samdporter@users.noreply.github.com>  <porter.samd@gmail.com>
 Matthew Strugari <matthew.strugari@dal.ca>
 Matthew Strugari <matthew.strugari@dal.ca> <56315593+mastergari@users.noreply.github.com>
+Imraj Singh <imraj.singh.20@ucl.ac.uk>
+Imraj Singh <imraj.singh.20@ucl.ac.uk> <72553490+Imraj-Singh@users.noreply.github.com>

CITATION.cff

@@ -81,23 +81,21 @@ authors:
     - family-names: Brusaferri
       given-names:  Ludovica
       affiliation:  University College London
-    - family-names: Pasca
-      given-names:  Edoardo
-      affiliation:  UK Research & Innovation
-      orcid:        'https://orcid.org/0000-0001-6957-2160'
     - family-names: Thomas
       given-names:  Benjamin
       orcid:        'https://orcid.org/0000-0002-9784-1177'
       affiliation:  University College London
+    - family-names: Pasca
+      given-names:  Edoardo
+      affiliation:  UK Research & Innovation
+      orcid:        'https://orcid.org/0000-0001-6957-2160'
     - family-names: Aguiar
       given-names:  Pablo
     - family-names: Niknejad
       given-names:  Tahereh
     - family-names: Sadki
       given-names:  Mustapha
       affiliation:  Brunel University (UK)
-    - family-names: Schmidtlein
-      given-names:  C Ross
     - family-names: Kerrouche
       given-names:  Nacer
       affiliation:  Hammersmith Imanet Ltd
@@ -110,16 +108,22 @@ authors:
     - family-names: Ehrhardt
       given-names:  Matthias J.
       orcid:        'https://orcid.org/0000-0001-8523-353X'
+    - family-names: Singh
+      given-names:  Imraj
+      orcid:        0000-0002-3775-9155
+      affiliation:  University College London (UK)
+    - family-names: Schmidtlein
+      given-names:  C Ross
+    - family-names: Ovtchinnikov
+      given-names:  Evgueni
+      orcid:        'https://orcid.org/0000-0002-9359-6514'
+      affiliation:  UK Research & Innovation
     - family-names: Valente
       given-names:  Patrick
       affiliation:  Brunel University (UK)
     - family-names: Jurjew
       given-names:  Nicole
       affiliation:  University College London
-    - family-names: Ovtchinnikov
-      given-names:  Evgueni
-      orcid:        'https://orcid.org/0000-0002-9359-6514'
-      affiliation:  UK Research & Innovation
     - family-names: Schramm
       given-names:  Georg
       affiliation:  Katholieke Universiteit Leuven (Belgium)