chore(deps): bump elliptic from 6.5.2 to 6.5.4

Bumps [elliptic](https://github.com/indutny/elliptic) from 6.5.2 to 6.5.4.
- [Release notes](https://github.com/indutny/elliptic/releases)
- [Commits](https://github.com/indutny/elliptic/compare/v6.5.2...v6.5.4)

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

package-lock.json

@@ -5153,18 +5153,26 @@
       "dev": true
     },
     "elliptic": {
-      "version": "6.5.2",
-      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-6.5.2.tgz",
-      "integrity": "sha512-f4x70okzZbIQl/NSRLkI/+tteV/9WqL98zx+SQ69KbXxmVrmjwsNUPn/gYJJ0sHvEak24cZgHIPegRePAtA/xw==",
+      "version": "6.5.4",
+      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-6.5.4.tgz",
+      "integrity": "sha512-iLhC6ULemrljPZb+QutR5TQGB+pdW6KGD5RSegS+8sorOZT+rdQFbsQFJgvN3eRqNALqJer4oQ16YvJHlU8hzQ==",
       "dev": true,
       "requires": {
-        "bn.js": "^4.4.0",
-        "brorand": "^1.0.1",
+        "bn.js": "^4.11.9",
+        "brorand": "^1.1.0",
         "hash.js": "^1.0.0",
-        "hmac-drbg": "^1.0.0",
-        "inherits": "^2.0.1",
-        "minimalistic-assert": "^1.0.0",
-        "minimalistic-crypto-utils": "^1.0.0"
+        "hmac-drbg": "^1.0.1",
+        "inherits": "^2.0.4",
+        "minimalistic-assert": "^1.0.1",
+        "minimalistic-crypto-utils": "^1.0.1"
+      },
+      "dependencies": {
+        "bn.js": {
+          "version": "4.12.0",
+          "resolved": "https://registry.npmjs.org/bn.js/-/bn.js-4.12.0.tgz",
+          "integrity": "sha512-c98Bf3tPniI+scsdk237ku1Dc3ujXQTSgyiPUDEOe7tRkhrqridvh8klBv0HCEso1OLOYcHuCv/cS6DNxKH+ZA==",
+          "dev": true
+        }
       }
     },
     "emoji-regex": {
@@ -11222,9 +11230,9 @@
       "dev": true
     },
     "postcss": {
-      "version": "7.0.36",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-7.0.36.tgz",
-      "integrity": "sha512-BebJSIUMwJHRH0HAQoxN4u1CN86glsrwsW0q7T+/m44eXOUAxSNdHRkNZPYz5vVUbg17hFgOQDE7fZk7li3pZw==",
+      "version": "7.0.25",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-7.0.25.tgz",
+      "integrity": "sha512-NXXVvWq9icrm/TgQC0O6YVFi4StfJz46M1iNd/h6B26Nvh/HKI+q4YZtFN/EjcInZliEscO/WL10BXnc1E5nwg==",
       "dev": true,
       "requires": {
         "chalk": "^2.4.2",