[skip ci] Update dependency gatsby-plugin-robots-txt to v1.5.6

Author: renovate-bot

package.json

@@ -55,7 +55,7 @@
     "gatsby-plugin-offline": "3.10.0",
     "gatsby-plugin-react-helmet": "3.10.0",
     "gatsby-plugin-react-helmet-canonical-urls": "1.4.0",
-    "gatsby-plugin-robots-txt": "1.5.5",
+    "gatsby-plugin-robots-txt": "1.5.6",
     "gatsby-plugin-root-import": "2.0.6",
     "gatsby-plugin-sass": "2.3.21",
     "gatsby-plugin-sharp": "2.14.1",

yarn.lock

@@ -9303,10 +9303,10 @@ [email protected]:
   dependencies:
     "@babel/runtime" "^7.12.5"
 
-[email protected].5:
-  version "1.5.5"
-  resolved "https://registry.yarnpkg.com/gatsby-plugin-robots-txt/-/gatsby-plugin-robots-txt-1.5.5.tgz#5ec156c2283307031d4890a7d036e11131037cea"
-  integrity sha512-wLIep04R0cnY+3t9uFVFitA/eLbI6o8xkrUPg6gVxnas/LtzMe5tUiMK5P+idC14B0ohY1y2zl2hP+Bu54/dHQ==
+[email protected].6:
+  version "1.5.6"
+  resolved "https://registry.yarnpkg.com/gatsby-plugin-robots-txt/-/gatsby-plugin-robots-txt-1.5.6.tgz#5a0d7ac47240ad538d988615a8a8ec648a6b641f"
+  integrity sha512-AxHbrw8WaYOxyu++LPIratjlNgBuu2qb5j3F+Ht+ooD/azutL+BAPbuYexz9CMPqTy1h/kiBxZsojbGLbWpvgA==
   dependencies:
     "@babel/runtime" "^7.11.2"
     generate-robotstxt "^8.0.3"