Visa Logo (#876)

* added visa.svg

* Removed the orange swoosh from visa.svg and compressed it

* run update_readme.py

* updated reference image and url (visa.png, visa.url).  also ran update_readme.py

images/svg/visa.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+aria-label="visa" role="img"
+viewBox="0 0 512 512"><path
+d="m0 0h512v512H0"
+fill="#fff"/><path d="M229 323h-32l20-133h33l-21 133Zm117-129c-6-3-16-6-29-6-31 0-54 18-54 44 0 19 16 30 28 36 13 6 17 11 17 16 0 9-10 13-19 13-13 0-20-2-31-7l-4-2-4 30c7 4 21 7 36 7 33 0 55-18 56-45 0-15-9-27-27-36-12-6-19-11-19-17 1-5 6-11 19-11 11 0 18 2 24 5l3 1 4-28Zm43 82 13-37 4-13 3 12 7 38h-27Zm40-86h-25c-8 0-13 3-17 11l-48 122h34l7-20h41l4 20h30l-26-133Zm-259 0-31 91-4-19c-6-21-24-44-44-55l29 116h34l50-133h-34Z M109 190H58l-1 3c40 11 67 38 78 70l-11-61c-2-9-8-11-15-12Z" fill="#00579F"/></svg>