Make style flat

Undecided discussion from badges/shields#3635 rudely removed style=popout in badges/shields#3747

base.json

@@ -3,6 +3,6 @@
   "label": "Add a label with `label=LABEL` in the query string",
   "message": "Add a message with `message=MESSAGE` in the query string",
   "color": "#75aadb",
-  "style": "popout",
+  "style": "flat",
   "logoSvg": "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<!-- Generator: Adobe Illustrator 22.1.0, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->\n<svg\n  version=\"1.1\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"\n  x=\"0px\" y=\"0px\"\n  viewBox=\"0 0 625.9 625.9\"\n  style=\"enable-background:new 0 0 625.9 625.9;\"\n  xml:space=\"preserve\"\n>\n  <style type=\"text/css\">\n    .st0{fill:#75AADB;}\n    .st2{fill:#FFFFFF;}\n  <\/style>\n  <g id=\"Blue_Gradient_Letters\">\n    <g>\n      <ellipse transform=\"matrix(0.7071 -0.7071 0.7071 0.7071 -127.9265 317.0317)\" class=\"st0\" cx=\"318.7\" cy=\"312.9\" rx=\"309.8\" ry=\"309.8\"/>\n      <g>\n        <path\n          class=\"st2\"\n          d=\"M424.7,411.8h33.6v26.1h-51.3L322,310.5h-45.3v101.3h44.3v26.1H209.5v-26.1h38.3V187.3l-38.3-4.7v-24.7\n            c14.5,3.3,27.1,5.6,42.9,5.6c23.8,0,48.1-5.6,71.9-5.6c46.2,0,89.1,21,89.1,72.3c0,39.7-23.8,64.9-60.7,75.6L424.7,411.8z\n            M276.7,285.3l24.3,0.5c59.3,0.9,82.1-21.9,82.1-52.3c0-35.5-25.7-49.5-58.3-49.5c-15.4,0-31.3,1.4-48.1,3.3V285.3z\"\n        />\n      <\/g>\n    <\/g>\n  <\/g>\n<\/svg>"
 }