fix: substack.png to Substack.svg

src/drivers/webextension/images/icons/Substack.svg

@@ -0,0 +1,5 @@
+<svg width="32" height="32" viewBox="0 0 32 32" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M28.3066 7.88461H2.46154V11.3757H28.3066V7.88461Z" fill="#FF6719"/>
+<path d="M2.46154 14.5385V30.7697L15.3835 23.5209L28.3077 30.7697V14.5385H2.46154Z" fill="#FF6719"/>
+<path d="M28.3066 1.23077H2.46154V4.72127H28.3066V1.23077Z" fill="#FF6719"/>
+</svg>

src/technologies/s.json

@@ -4907,7 +4907,7 @@
       "x-cluster": "substack",
       "x-served-by": "Substack"
     },
-    "icon": "substack.png",
+    "icon": "Substack.svg",
     "website": "http://substack.com/"
   },
   "Sucuri": {