Bump acorn from 5.7.3 to 5.7.4

Bumps [acorn](https://github.com/acornjs/acorn) from 5.7.3 to 5.7.4.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/5.7.3...5.7.4)

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

package-lock.json

@@ -52,9 +52,9 @@
       }
     },
     "acorn": {
-      "version": "5.7.3",
-      "resolved": "https://registry.npmjs.org/acorn/-/acorn-5.7.3.tgz",
-      "integrity": "sha512-T/zvzYRfbVojPWahDsE5evJdHb3oJoQfFbsrKM7w5Zcs++Tr257tia3BmMP8XYVjp1S9RZXQMh7gao96BlqZOw==",
+      "version": "5.7.4",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-5.7.4.tgz",
+      "integrity": "sha512-1D++VG7BhrtvQpNbBzovKNc1FLGGEE/oGe7b9xJm/RFHMBeUaUGpluV9RLjZa47YFdPcDAenEYuq9pQPcMdLJg==",
       "dev": true
     },
     "after": {
@@ -1506,7 +1506,7 @@
           "dependencies": {
             "readable-stream": {
               "version": "1.0.34",
-              "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
+              "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
               "integrity": "sha1-Elgg40vIQtLyqq+v5MKRbuMsFXw=",
               "dev": true,
               "optional": true,
@@ -1767,7 +1767,7 @@
         },
         "readable-stream": {
           "version": "1.0.34",
-          "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
+          "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
           "integrity": "sha1-Elgg40vIQtLyqq+v5MKRbuMsFXw=",
           "dev": true,
           "optional": true,
@@ -1847,7 +1847,7 @@
         },
         "readable-stream": {
           "version": "1.0.34",
-          "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
+          "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
           "integrity": "sha1-Elgg40vIQtLyqq+v5MKRbuMsFXw=",
           "dev": true,
           "optional": true,
@@ -2152,7 +2152,7 @@
           "dependencies": {
             "readable-stream": {
               "version": "1.0.34",
-              "resolved": "http://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
+              "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-1.0.34.tgz",
               "integrity": "sha1-Elgg40vIQtLyqq+v5MKRbuMsFXw=",
               "dev": true,
               "optional": true,