Update tag filtering in webdash

- Thanks @matthewpeterkort for the help and recommendation on this!

tag-filtering-tests/task-bar-foo.json

@@ -0,0 +1,15 @@
+{
+  "name": "Task with tag bar:foo",
+  "executors": [
+    {
+      "image": "alpine",
+      "command": [
+        "echo",
+        "hello"
+      ]
+    }
+  ],
+  "tags": {
+    "bar": "foo"
+  }
+}

tag-filtering-tests/task-foo-bar.json

@@ -0,0 +1,15 @@
+{
+  "name": "Task with tag foo:bar",
+  "executors": [
+    {
+      "image": "alpine",
+      "command": [
+        "echo",
+        "hello"
+      ]
+    }
+  ],
+  "tags": {
+    "foo": "bar"
+  }
+}

tag-filtering-tests/task-foo-baz.json

@@ -0,0 +1,15 @@
+{
+  "name": "Task with tag foo:baz",
+  "executors": [
+    {
+      "image": "alpine",
+      "command": [
+        "echo",
+        "hello"
+      ]
+    }
+  ],
+  "tags": {
+    "foo": "baz"
+  }
+}

tag-filtering-tests/task-foo-nil.json

@@ -0,0 +1,15 @@
+{
+  "name": "Task with tag foo:",
+  "executors": [
+    {
+      "image": "alpine",
+      "command": [
+        "echo",
+        "hello"
+      ]
+    }
+  ],
+  "tags": {
+    "foo": ""
+  }
+}

tag-filtering-tests/task-nil-bar.json

@@ -0,0 +1,15 @@
+{
+  "name": "Task with tag :bar",
+  "executors": [
+    {
+      "image": "alpine",
+      "command": [
+        "echo",
+        "hello"
+      ]
+    }
+  ],
+  "tags": {
+    "": "bar"
+  }
+}

tag-filtering-tests/task-nil-nil.json

@@ -0,0 +1,15 @@
+{
+  "name": "Task with tag :",
+  "executors": [
+    {
+      "image": "alpine",
+      "command": [
+        "echo",
+        "hello"
+      ]
+    }
+  ],
+  "tags": {
+    "": ""
+  }
+}

webdash/src/Pages.js

@@ -58,7 +58,10 @@ function TaskList({pageToken, setPageToken,
     for (var i = 0; i < tagsFilter.length; i++) {
       var tag = tagsFilter[i];
       if (tag.key !== "") {
-        params.set("tags["+tag.key+"]", tag.value);
+        params.set("tag_key", tag.key);
+      };
+      if (tag.value !== "") {
+        params.set("tag_value", tag.value);
       };
     };
     if (pageToken !== "") {