Bump node-fetch from 2.6.1 to 2.6.7 in /backend

Bumps [node-fetch](https://github.com/node-fetch/node-fetch) from 2.6.1 to 2.6.7.
- [Release notes](https://github.com/node-fetch/node-fetch/releases)
- [Commits](https://github.com/node-fetch/node-fetch/compare/v2.6.1...v2.6.7)

---
updated-dependencies:
- dependency-name: node-fetch
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

backend/package-lock.json

@@ -2392,9 +2392,12 @@
       "integrity": "sha512-hZXc7K2e+PgeI1eDBe/10Ard4ekbfrrqG8Ep+8Jmf4JID2bNg7NvCPOZN+kfF574pFQI7mum2AUqDidoKqcTOw=="
     },
     "node-fetch": {
-      "version": "2.6.1",
-      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.6.1.tgz",
-      "integrity": "sha512-V4aYg89jEoVRxRb2fJdAg8FHvI7cEyYdVAh94HH0UIK8oJxUfkjlDQN9RbMx+bEjP7+ggMiFRprSti032Oipxw=="
+      "version": "2.6.7",
+      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.6.7.tgz",
+      "integrity": "sha512-ZjMPFEfVx5j+y2yF35Kzx5sF7kDzxuDj6ziH4FFbOp87zKDZNx8yExJIb05OGF4Nlt9IHFIMBkRl41VdvcNdbQ==",
+      "requires": {
+        "whatwg-url": "^5.0.0"
+      }
     },
     "node-id3": {
       "version": "0.1.16",
@@ -3261,6 +3264,11 @@
         "punycode": "^2.1.1"
       }
     },
+    "tr46": {
+      "version": "0.0.3",
+      "resolved": "https://registry.npmjs.org/tr46/-/tr46-0.0.3.tgz",
+      "integrity": "sha1-gYT9NH2snNwYWZLzpmIuFLnZq2o="
+    },
     "traverse": {
       "version": "0.3.9",
       "resolved": "https://registry.npmjs.org/traverse/-/traverse-0.3.9.tgz",
@@ -3472,6 +3480,20 @@
         "extsprintf": "^1.2.0"
       }
     },
+    "webidl-conversions": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-3.0.1.tgz",
+      "integrity": "sha1-JFNCdeKnvGvnvIZhHMFq4KVlSHE="
+    },
+    "whatwg-url": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/whatwg-url/-/whatwg-url-5.0.0.tgz",
+      "integrity": "sha1-lmRU6HZUYuN2RNNib2dCzotwll0=",
+      "requires": {
+        "tr46": "~0.0.3",
+        "webidl-conversions": "^3.0.0"
+      }
+    },
     "which": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",