Removed default-branch library since it's no longer used (#3019)

plugins/techdocs-backend/package.json

@@ -26,7 +26,6 @@
     "@types/dockerode": "^2.5.34",
     "@types/express": "^4.17.6",
     "command-exists-promise": "^2.0.2",
-    "default-branch": "^1.0.8",
     "dockerode": "^3.2.1",
     "express": "^4.17.1",
     "express-promise-router": "^3.0.3",

yarn.lock

@@ -9780,11 +9780,6 @@ deepmerge@4.2.2, deepmerge@^4.2.2:
   resolved "https://registry.npmjs.org/deepmerge/-/deepmerge-4.2.2.tgz#44d2ea3679b8f4d4ffba33f03d865fc1e7bf4955"
   integrity sha512-FJ3UgI4gIl+PHZm53knsuSFpE+nESMr7M4v9QcgB7S63Kj/6WqMiFQJpBBYz1Pt+66bZpP3Q7Lye0Oo9MPKEdg==
 
-default-branch@^1.0.8:
-  version "1.0.8"
-  resolved "https://registry.npmjs.org/default-branch/-/default-branch-1.0.8.tgz#0e2f36a90e3b0d9f73cdf8e02841364ed35b8b54"
-  integrity sha512-pViUZEnaxd/Hbu880MEXF7XqV8RJ1ssDlkvzx+woQhcKW8px3BrVDvwBGn09zRiKZ+gOLipK7ft5x3no+3vb8A==
-
 default-gateway@^4.2.0:
   version "4.2.0"
   resolved "https://registry.npmjs.org/default-gateway/-/default-gateway-4.2.0.tgz#167104c7500c2115f6dd69b0a536bb8ed720552b"