Add Slackware (#2289)

Add Slackware

_data/simple-icons.json

@@ -3830,6 +3830,11 @@
             "hex": "4A154B",
             "source": "https://slack.com/brand-guidelines"
         },
+        {
+            "title": "Slackware",
+            "hex": "000000",
+            "source": "https://en.wikipedia.org/wiki/Slackware"
+        },
         {
             "title": "Slashdot",
             "hex": "026664",

icons/slackware.svg

@@ -0,0 +1 @@
+<svg role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><title>Slackware icon</title><path d="M12.924 1.453c-.584-.01-1.251 0-1.485.027-2.46.282-4.138 1.3-4.753 2.891-.218.552-.274 1.002-.243 1.772.048 1.209.419 2.004 1.262 2.742 1.225 1.06 2.98 1.508 5.998 1.508 2.737 0 3.71.413 3.916 1.675.313 1.867-1.57 3.07-4.414 2.827-1.878-.16-3.496-.912-4.223-1.967a7.772 7.772 0 01-.355-.621c-.382-.759-.64-.977-1.176-.977-.43.005-.732.165-.918.494l-.133.239V16.093l.137.297c.165.344.4.546.744.63.35.09.794-.036 1.42-.402l.5-.29.826.185c1.82.403 2.75.523 4.065.523 1.103.005 1.548-.046 2.455-.285 1.124-.297 1.974-.785 2.717-1.57.8-.844 1.15-1.853 1.097-3.147-.069-1.628-.695-2.698-2-3.414-.96-.525-2.292-.79-4.377-.88-2.042-.086-2.794-.155-3.515-.32-.51-.121-.785-.25-1.076-.515-.653-.589-.59-1.755.136-2.482.642-.637 1.511-.928 2.774-.928 1.432.005 2.393.27 3.412.955.185.127.721.62 1.193 1.092.886.902 1.135 1.082 1.506 1.082.244 0 .59-.163.732-.344.26-.329.303-.63.303-2.2 0-1.661-.043-1.91-.377-2.282-.387-.425-.848-.42-1.75.031l-.59.297-.63-.17c-1.496-.392-2.038-.477-3.178-.504zM0 14v9h24v-1H1v-8H0Z"/></svg>