add GitHub action

Processes geojson to topojson on a change to the geojson file.

.github/scripts/minify-map-json.sh

@@ -0,0 +1,4 @@
+npm install -g mapshaper
+mapshaper ./boundaries.geo.json snap -clean -o force precision=0.0001 format=geojson ./boundaries.geo.json
+npm install -g topojson-server
+geo2topo ./boundaries.geo.json -q 50000 > ./website/data/boundaries.topo.json

.github/workflows/minify-map-json.yml

@@ -0,0 +1,23 @@
+name: Minify Map JSON
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - boundaries.geo.json
+jobs:
+  mergeData:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Update TopoJSON boundaries
+        run: ./.github/scripts/minify-map-json.sh
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v3
+        with:
+          commit-message: Update TopoJSON boundaries
+          title: Update TopoJSON boundaries
+          body: Clean and minify GeoJSON and process to TopoJSON
+          branch: geo-to-topo