integrations: Update Bitbucket logo.

Converts logo from PNG to SVG format.

static/images/integrations/logos/bitbucket.svg

@@ -0,0 +1 @@
+<svg width="256" height="231" xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMidYMid"><defs><linearGradient x1="108.633%" y1="13.818%" x2="46.927%" y2="78.776%" id="a"><stop stop-color="#0052CC" offset="18%"/><stop stop-color="#2684FF" offset="100%"/></linearGradient></defs><g fill="none"><path d="M101.272 152.561h53.449l12.901-75.32H87.06z"/><path d="M8.308 0A8.202 8.202 0 0 0 .106 9.516l34.819 211.373a11.155 11.155 0 0 0 10.909 9.31h167.04a8.202 8.202 0 0 0 8.201-6.89l34.82-213.752a8.202 8.202 0 0 0-8.203-9.514L8.308 0zm146.616 152.768h-53.315l-14.436-75.42h80.67l-12.919 75.42z" fill="#2684FF"/><path d="M244.61 77.242h-76.916l-12.909 75.36h-53.272l-62.902 74.663a11.105 11.105 0 0 0 7.171 2.704H212.73a8.196 8.196 0 0 0 8.196-6.884l23.686-145.843z" fill="url(#a)"/></g></svg>

zerver/lib/integrations.py

@@ -267,7 +267,7 @@ WEBHOOK_INTEGRATIONS = [
     WebhookIntegration(
         'bitbucket2',
         ['version-control'],
-        logo='static/images/integrations/logos/bitbucket.png',
+        logo='static/images/integrations/logos/bitbucket.svg',
         display_name='Bitbucket',
         stream_name='bitbucket'
     ),