Add gradle icon (#251)

* Add javascript icon

* Move the JS slightly closer to the centre

* Add Git icon

* Add gradle icon

* Add new gradle svg and reference

* Fix gradle logo, add it to README

images/reference/gradle-elephant-icon-dark-green-secondary.svg

@@ -0,0 +1 @@
+<svg id="Layer_1" data-name="Layer 1" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 90 66.06"><defs><style>.cls-1{fill:#02303a;}</style></defs><title>gradle-elephant-icon-dark-green-secondary</title><path class="cls-1" d="M85.11,4.18a14.27,14.27,0,0,0-19.83-.34,1.38,1.38,0,0,0,0,2L67,7.6a1.36,1.36,0,0,0,1.78.12A8.18,8.18,0,0,1,79.5,20.06C68.17,31.38,53.05-.36,18.73,16a4.65,4.65,0,0,0-2,6.54l5.89,10.17a4.64,4.64,0,0,0,6.3,1.73l.14-.08-.11.08L31.53,33a60.29,60.29,0,0,0,8.22-6.13,1.44,1.44,0,0,1,1.87-.06h0a1.34,1.34,0,0,1,.06,2A61.61,61.61,0,0,1,33,35.34l-.09,0-2.61,1.46a7.34,7.34,0,0,1-3.61.94,7.45,7.45,0,0,1-6.47-3.71l-5.57-9.61C4,32-2.54,46.56,1,65a1.36,1.36,0,0,0,1.33,1.11H8.61A1.36,1.36,0,0,0,10,64.87a9.29,9.29,0,0,1,18.42,0,1.35,1.35,0,0,0,1.34,1.19H35.9a1.36,1.36,0,0,0,1.34-1.19,9.29,9.29,0,0,1,18.42,0A1.36,1.36,0,0,0,57,66.06H63.1a1.36,1.36,0,0,0,1.36-1.34c.14-8.6,2.46-18.48,9.07-23.43C96.43,24.16,90.41,9.48,85.11,4.18ZM61.76,30.05l-4.37-2.19h0a2.74,2.74,0,1,1,4.37,2.2Z"/></svg>

images/svg/git.svg

@@ -3,4 +3,4 @@ aria-label="Git" role="img"
 viewBox="0 0 512 512">
 <rect width="512" height="512" rx="15%" fill="#fff"/>
 <path fill="#f05133" d="M440.8 238.9L273 71.2a24.7 24.7 0 0 0-35 0l-34.8 34.9 44.2 44.1a29.4 29.4 0 0 1 37.2 37.5l42.5 42.5a29.4 29.4 0 1 1-17.6 16.6l-39.7-39.7v104.5a29.4 29.4 0 1 1-24.2-.9V205.3a29.4 29.4 0 0 1-16-38.6l-43.5-43.5-115 115a24.7 24.7 0 0 0 0 34.9L239 440.8a24.7 24.7 0 0 0 35 0l166.9-167a24.7 24.7 0 0 0 0-34.9"/>
-</svg>
+</svg>

images/svg/gradle.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+aria-label="gradle" role="img"
+viewBox="0 0 512 512"><rect
+width="512" height="512"
+rx="15%"
+fill="#fff"/><path d="m427,132.7a61,61 0 0 0-85,-1 6,6 0 0 0 0,9l7,8a6,6 0 0 0 8,1 35,35 0 0 1 46,53c-48,48-113,-87-259,-17a20,20 0 0 0-9,28l25,43a20,20 0 0 0 27,7l1,0 0,0 11,-6a257,257 0 0 0 35,-26 6,6 0 0 1 8,-0v0a6,6 0 0 1 0,9 263,263 0 0 1-37,28h-0l-11,6a31,31 0 0 1-15,4 32,32 0 0 1-28,-16L126,219C81,259 53,314 68.13,392.26a6,6 0 0 0 6,4.74H100.6a6,6 0 0 0 5.93,-5.3 40,40 0 0 1 78.62,0 6,6 0 0 0 5.72,5.08h26.2a6,6 0 0 0 5.7,-5.1 40,40 0 0 1 78.6,0 6,6 0 0 0 5.7,5h26a6,6 0 0 0 5.8,-5.72c1,-37 10,-79 38.7,-100 98,-73 72,-136 49.4,-158.3zm-100,110-19,-9v0a12,12 0 1 1 19,9z" style="fill:#02303a"/></svg>

images/svg/javascript.svg

@@ -3,4 +3,4 @@ aria-label="javascript" role="img"
 viewBox="0 0 512 512"><rect
 width="512" height="512"
 rx="15%"
-fill="#f7df1e"/><path d="m324,370c10,17 24,29 47,29 20,0 33,-10 33,-24 0,-16 -13,-22 -35,-32l-12,-5c-35,-15 -58,-33 -58,-72 0,-36 27,-64 70,-64 31,0 53,11 68,39l-37,24c-8,-15 -17,-21 -31,-21 -14,0 -23,9 -23,21 0,14 9,20 30,29l12,5c41,18 64,35 64,76 0,43 -34,67 -80,67 -45,0 -74,-21 -88,-49zm-170,4c8,13 14,25 31,25 16,0 26,-6 26,-30V203h48v164c0,50 -29,72 -72,72 -39,0 -61,-20 -72,-44z"/></svg>
+fill="#f7df1e"/><path d="m324,370c10,17 24,29 47,29 20,0 33,-10 33,-24 0,-16 -13,-22 -35,-32l-12,-5c-35,-15 -58,-33 -58,-72 0,-36 27,-64 70,-64 31,0 53,11 68,39l-37,24c-8,-15 -17,-21 -31,-21 -14,0 -23,9 -23,21 0,14 9,20 30,29l12,5c41,18 64,35 64,76 0,43 -34,67 -80,67 -45,0 -74,-21 -88,-49zm-170,4c8,13 14,25 31,25 16,0 26,-6 26,-30V203h48v164c0,50 -29,72 -72,72 -39,0 -61,-20 -72,-44z"/></svg>