Add update-docker.ps1

scripts/update-docker.ps1

@@ -0,0 +1,21 @@
+# PowerShell script to update Termux Package Builder Docker Image
+#
+# Usage example:
+#
+# .\scripts\update-docker.ps1
+
+Set-Variable -Name CONTAINER -Value "termux-package-builder"
+Set-Variable -Name IMAGE -Value "termux/package-builder"
+
+docker pull $IMAGE
+
+Set-Variable -Name LATEST -Value (docker inspect --format "{{.Id}}" $IMAGE)
+Set-Variable -Name RUNNING -Value (docker inspect --format "{{.Image}}" $CONTAINER)
+
+if ($LATEST -eq $RUNNING) {
+    Write-Output "Image '$IMAGE' used in the container '$CONTAINER' is already up to date"
+} else {
+    Write-Output "Image '$IMAGE' used in the container '$CONTAINER' has been updated - removing the outdated container"
+    docker stop $CONTAINER
+    docker rm -f $CONTAINER
+}