simple ubuntu packer image build

```

ubuntu.pkr.hcl

@@ -0,0 +1,29 @@
+packer {
+     required_version = ">= 0.0.2"
+ }
+ 
+ source "amazon-ebs" "ubuntu" {
+    ami_name      = "test-custom-ubuntu20.04-ami"
+    instance_type = "t2.micro"
+    region        = "us-west-1"
+    ssh_username  = "ubuntu"
+    # 22.04 "ami-0cbd40f694b804622" # 20.04 "ami-0da7657fe73215c0c"
+    source_ami    = "ami-0da7657fe73215c0c"
+    temporary_key_pair_name = "packer_ubuntu"
+    temporary_key_pair_type = "ed25519"
+}
+  
+build {
+    name    = "ubuntu-ami"
+    sources = ["source.amazon-ebs.ubuntu"]
+  
+    provisioner "shell" {
+        inline = [
+            "sleep 30",
+            "sudo apt-get update",
+            "sudo apt-get install -y nginx",
+            "sudo service nginx start"
+        ]
+    }
+ 
+}