designers: converted jpg to png (#2794)

* designers/tirotypeworks : converted jpg to png

* designers/paulhanslow: converted jpg to png

* designers/kajaslojewska: converted jpg to png

* designers/johnhudson: converted jpg to png

Co-authored-by: Rosalie Wagner <rose.wagner@free.fr>

catalog/designers/johnhudson/info.pb

@@ -1,5 +1,5 @@
 designer: "John Hudson"
 link: "https://www.tiro.com/"
 avatar: {
-  file_name: "john_hudson.jpg"
+  file_name: "johnhudson.png"
 }

catalog/designers/kajaslojewska/info.pb

@@ -1,5 +1,5 @@
 designer: "Kaja Słojewska"
 link: "https://nomadfonts.com/"
 avatar: {
-  file_name: "KajaSlojewska.jpg"
+  file_name: "kajaslojewska.png"
 }

catalog/designers/paulhanslow/info.pb

@@ -1,5 +1,5 @@
 designer: "Paul Hanslow"
 link: "https://www.tiro.com/"
 avatar: {
-  file_name: "PaulHanslow.jpg"
+  file_name: "paulhanslow.png"
 }

catalog/designers/tirotypeworks/info.pb

@@ -1,5 +1,5 @@
 designer: "Tiro Typeworks"
 link: "https://www.tiro.com/"
 avatar: {
-  file_name: "TiroLogo.jpg"
+  file_name: "tirotypeworks.png"
 }