Update `https-proxy-agent` as per security advisory (#7289)

Security advisory: https://www.npmjs.com/advisories/1184

The package `pac-proxy-agent` (which we use via `pubnub`) hasn't
released an update yet, so we're forced to use a resolution for the
time being. The updated version appears to be compatible.

package.json

@@ -49,7 +49,8 @@
     "rollback": "./development/rollback.sh"
   },
   "resolutions": {
-    "3box/ipfs/ipld-zcash/zcash-bitcore-lib/lodash": "^4.17.12"
+    "3box/ipfs/ipld-zcash/zcash-bitcore-lib/lodash": "^4.17.12",
+    "pubnub/superagent-proxy/proxy-agent/pac-proxy-agent/https-proxy-agent": "^3.0.0"
   },
   "dependencies": {
     "3box": "^1.10.2",

yarn.lock

@@ -3062,6 +3062,13 @@ agent-base@4, agent-base@^4.1.0, agent-base@^4.2.0:
   dependencies:
     es6-promisify "^5.0.0"
 
+agent-base@^4.3.0:
+  version "4.3.0"
+  resolved "https://registry.yarnpkg.com/agent-base/-/agent-base-4.3.0.tgz#8165f01c436009bccad0b1d122f05ed770efc6ee"
+  integrity sha512-salcGninV0nPrwpGNn4VTXBb1SOuXQBiqbrNXoeizJsHrsL6ERFM2Ne3JUSBWRE6aeNJI2ROP/WEEIDUiDe3cg==
+  dependencies:
+    es6-promisify "^5.0.0"
+
 agentkeepalive@^3.5.2:
   version "3.5.2"
   resolved "https://registry.yarnpkg.com/agentkeepalive/-/agentkeepalive-3.5.2.tgz#a113924dd3fa24a0bc3b78108c450c2abee00f67"
@@ -13454,7 +13461,7 @@ https-did-resolver@^0.1.0:
     did-resolver "0.0.6"
     xmlhttprequest "^1.8.0"
 
-https-proxy-agent@2.2.1, https-proxy-agent@^2.1.1, https-proxy-agent@^2.2.1:
+https-proxy-agent@2.2.1, https-proxy-agent@^2.1.1:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/https-proxy-agent/-/https-proxy-agent-2.2.1.tgz#51552970fa04d723e04c56d04178c3f92592bbc0"
   integrity sha512-HPCTS1LW51bcyMYbxUIOO4HEOlQ1/1qRaFWcyxvwaqUS9TY88aoEuHUY33kuAh1YhVVaDQhLZsnPd+XNARWZlQ==
@@ -13462,6 +13469,22 @@ https-proxy-agent@2.2.1, https-proxy-agent@^2.1.1, https-proxy-agent@^2.2.1:
     agent-base "^4.1.0"
     debug "^3.1.0"
 
+https-proxy-agent@^2.2.1:
+  version "2.2.2"
+  resolved "https://registry.yarnpkg.com/https-proxy-agent/-/https-proxy-agent-2.2.2.tgz#271ea8e90f836ac9f119daccd39c19ff7dfb0793"
+  integrity sha512-c8Ndjc9Bkpfx/vCJueCPy0jlP4ccCCSNDp8xwCZzPjKJUm+B+u9WX2x98Qx4n1PiMNTWo3D7KK5ifNV/yJyRzg==
+  dependencies:
+    agent-base "^4.3.0"
+    debug "^3.1.0"
+
+https-proxy-agent@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/https-proxy-agent/-/https-proxy-agent-3.0.0.tgz#0106efa5d63d6d6f3ab87c999fa4877a3fd1ff97"
+  integrity sha512-y4jAxNEihqvBI5F3SaO2rtsjIOnnNA8sEbuiP+UhJZJHeM2NRm6c09ax2tgqme+SgUUvjao2fJXF4h3D6Cb2HQ==
+  dependencies:
+    agent-base "^4.3.0"
+    debug "^3.1.0"
+
 human-standard-collectible-abi@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/human-standard-collectible-abi/-/human-standard-collectible-abi-1.0.2.tgz#077bae9ed1b0b0b82bc46932104b4b499c941aa0"