Bug 41587: Fix critical and high severity node dependency vulnerabilities

- Upgrade gulp-exec to ^5.0.0 (fixes lodash.template HIGH)
- Add resolution for form-data ^2.5.4 (CRITICAL)
- Add resolution for braces ^3.0.3 (HIGH)
- Add resolution for qs ^6.14.1 (HIGH)

Test plan:
- yarn audit --level high should show 0 vulnerabilities
- yarn build && yarn build:prod should complete without errors
- yarn cypress run should return without (or currently expected) errors

@RM: You will need to push yarn.lock as well

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@openfifth.co.uk>

package.json

@@ -26,7 +26,7 @@
     "gulp": "^4.0.2",
     "gulp-autoprefixer": "^4.0.0",
     "gulp-concat-po": "^1.0.0",
-    "gulp-exec": "^4.0.0",
+    "gulp-exec": "^5.0.0",
     "gulp-rename": "^2.0.0",
     "gulp-rtlcss": "^1.4.1",
     "gulp-sass": "^5.1.0",
@@ -69,7 +69,10 @@
   },
   "resolutions": {
     "minimatch": "^3.0.2",
-    "lodash": "^4.17.12"
+    "lodash": "^4.17.12",
+    "form-data": "^2.5.4",
+    "braces": "^3.0.3",
+    "qs": "^6.14.1"
   },
   "author": "",
   "license": "GPL-3.0",