Use scraping to get latest version of node/npm

In FreeBSD VM hosted on Google GCE, with `pkg search` command, it fails
to retrieve the latest list even after `pkg update -f` with `latest`
repository selected (checked with `pkg -vv search`). There seems to be
some caching mechanism involved, which I couldn't find a way to avoid.

Author: am11

.cirrus.yml

@@ -5,18 +5,18 @@ freebsd_build_task:
 
   env:
     matrix:
-      - node_js: "11"
-        nodePattern: "^node-11.*V8"
-        npmPattern: "^npm-6\\."
-      - node_js: "10"
-        nodePattern: "^node10-.*V8"
-        npmPattern: "^npm-node10-"
-      - node_js: "8"
-        nodePattern: "^node8-.*V8"
-        npmPattern: "^npm-node8-"
-      - node_js: "6"
-        nodePattern: "^node6-.*V8"
-        npmPattern: "^npm-node6-"
+      - node_js: 11
+        nodeTxzKey: node-11
+        npmTxzKey: npm-6
+      - node_js: 10
+        nodeTxzKey: node10
+        npmTxzKey: npm-node10
+      - node_js: 8
+        nodeTxzKey: node8
+        npmTxzKey: npm-node8
+      - node_js: 6
+        nodeTxzKey: node6
+        npmTxzKey: npm-node6
 
   env:
     matrix:
@@ -38,8 +38,12 @@ freebsd_build_task:
         $execPrefix pkg install -y python2 > /dev/null;
       fi
     - $execPrefix pkg install -y c-ares gmake icu libnghttp2 libuv git > /dev/null
-    - $execPrefix pkg add http://pkg.freebsd.org/$abi/latest/All/$(pkg search node | grep $nodePattern | cut -d' ' -f 1).txz
-    - $execPrefix pkg add http://pkg.freebsd.org/$abi/latest/All/$(pkg search npm | grep $npmPattern | cut -d' ' -f 1).txz
+    - |
+      fetch http://pkg.freebsd.org/$abi/latest/All/ -o list
+      nodeTxz=$(sed -n "/\"$nodeTxzKey/s/.*\"\($nodeTxzKey[^\"]*\).*/\1/p" list)
+      npmTxz=$(sed -n "/\"$npmTxzKey/s/.*\"\($npmTxzKey[^\"]*\).*/\1/p" list)
+      $execPrefix pkg add http://pkg.freebsd.org/$abi/latest/All/$nodeTxz
+      $execPrefix pkg add http://pkg.freebsd.org/$abi/latest/All/$npmTxz
     - $execPrefix node --version
     - $execPrefix npm --version
     - $execPrefix clang++ --version