don't apply logoColor param to multi-coloured logos (#2889)

This stops us from doing this:

![](https://img.shields.io/badge/logo-npm-blue.svg?logo=npm&logoColor=green) - https://img.shields.io/badge/logo-npm-blue.svg?logo=npm&logoColor=green
but still allows us to do this
![](https://img.shields.io/badge/logo-discord-blue.svg?logo=discord&logoColor=green) - https://img.shields.io/badge/logo-discord-blue.svg?logo=discord&logoColor=green

lib/load-logos.js

@@ -16,10 +16,13 @@ function loadLogos() {
     // filename is eg, github.svg
     const svg = fs.readFileSync(`${logoDir}/${filename}`).toString()
     const base64 = svg2base64(svg)
+    // logo is monochrome if it only has one fill= statement
+    const isMonochrome = (svg.match(/fill="(.+?)"/g) || []).length === 1
 
     // eg, github
     const name = filename.slice(0, -'.svg'.length).toLowerCase()
     logos[name] = {
+      isMonochrome,
       svg,
       base64,
     }

lib/logos.js

@@ -55,9 +55,9 @@ function getShieldsIcon({ name, color }) {
     return undefined
   }
 
-  const { svg, base64 } = logos[key]
+  const { svg, base64, isMonochrome } = logos[key]
   const svgColor = toSvgColor(color)
-  if (svgColor) {
+  if (svgColor && isMonochrome) {
     return svg2base64(svg.replace(/fill="(.+?)"/g, `fill="${svgColor}"`))
   } else {
     return base64

lib/logos.spec.js

@@ -24,13 +24,18 @@ describe('Logo helpers', function() {
   })
 
   test(prepareNamedLogo, () => {
-    // These two strings are identical except for characters 159-165 which
-    // differ.
-    given({ name: 'npm' }).expect(
+    // NPM uses multiple colors so the color param should be ignored
+    const npmLogo =
       'data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCA0MCA0MCI+PHBhdGggZD0iTTAgMGg0MHY0MEgwVjB6IiBmaWxsPSIjY2IwMDAwIi8+PHBhdGggZmlsbD0iI2ZmZiIgZD0iTTcgN2gyNnYyNmgtN1YxNGgtNnYxOUg3eiIvPjwvc3ZnPgo='
+    given({ name: 'npm' }).expect(npmLogo)
+    given({ name: 'npm', color: 'blue' }).expect(npmLogo)
+
+    // dependabot only uses one color so the color param should be respected
+    given({ name: 'dependabot' }).expect(
+      'data:image/svg+xml;base64,PHN2ZyB2aWV3Qm94PSIwIDAgMjQgMjQiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgZmlsbD0iI2ZmZiI+PHBhdGggZD0iTTkuNzAyLjc3OHY0LjY0OWgzLjA2OFY2Ljk4SDEuNTI4djcuMjM0SDB2NC42NDloMS41Mjh2My42MTdoMjAuOTQ0di0zLjYxN0gyNHYtNC42NDloLTEuNTI4VjYuOThoLTguMTc0Vi43Nzh6bS0uNTIzIDExLjg3bDEuMDIgMS4wNDQtMy4wNDQgMy4wOTUtMi4wNS0yLjA1IDEuMDItMS4wNDUgMS4wMyAxLjAzMnptOC42OTcgMGwxLjAxOCAxLjA0NC0zLjA2OCAzLjA5NS0yLjAzNy0yLjA1IDEuMDE5LTEuMDQ1IDEuMDE4IDEuMDMyeiIvPjwvc3ZnPg=='
     )
-    given({ name: 'npm', color: 'blue' }).expect(
-      'data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCA0MCA0MCI+PHBhdGggZD0iTTAgMGg0MHY0MEgwVjB6IiBmaWxsPSIjMDA3ZWM2Ii8+PHBhdGggZmlsbD0iIzAwN2VjNiIgZD0iTTcgN2gyNnYyNmgtN1YxNGgtNnYxOUg3eiIvPjwvc3ZnPgo='
+    given({ name: 'dependabot', color: 'blue' }).expect(
+      'data:image/svg+xml;base64,PHN2ZyB2aWV3Qm94PSIwIDAgMjQgMjQiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgZmlsbD0iIzAwN2VjNiI+PHBhdGggZD0iTTkuNzAyLjc3OHY0LjY0OWgzLjA2OFY2Ljk4SDEuNTI4djcuMjM0SDB2NC42NDloMS41Mjh2My42MTdoMjAuOTQ0di0zLjYxN0gyNHYtNC42NDloLTEuNTI4VjYuOThoLTguMTc0Vi43Nzh6bS0uNTIzIDExLjg3bDEuMDIgMS4wNDQtMy4wNDQgMy4wOTUtMi4wNS0yLjA1IDEuMDItMS4wNDUgMS4wMyAxLjAzMnptOC42OTcgMGwxLjAxOCAxLjA0NC0zLjA2OCAzLjA5NS0yLjAzNy0yLjA1IDEuMDE5LTEuMDQ1IDEuMDE4IDEuMDMyeiIvPjwvc3ZnPg=='
     )
 
     it('preserves color if light logo on dark background', function() {