Add Alpine 3.20 and drop 3.18

Author: jnoordsij

1.21/alpine3.18/Dockerfile renamed to 1.21/alpine3.20/Dockerfile

@@ -383,8 +383,8 @@
     "variants": [
       "bookworm",
       "bullseye",
+      "alpine3.20",
       "alpine3.19",
-      "alpine3.18",
       "windows/windowsservercore-ltsc2022",
       "windows/windowsservercore-1809",
       "windows/nanoserver-ltsc2022",
@@ -775,8 +775,8 @@
     "variants": [
       "bookworm",
       "bullseye",
+      "alpine3.20",
       "alpine3.19",
-      "alpine3.18",
       "windows/windowsservercore-ltsc2022",
       "windows/windowsservercore-1809",
       "windows/nanoserver-ltsc2022",

1.22/alpine3.18/Dockerfile renamed to 1.22/alpine3.20/Dockerfile

@@ -155,8 +155,8 @@ for version in "${versions[@]}"; do
 			"bookworm",
 			"bullseye",
 			(
+				"3.20",
 				"3.19",
-				"3.18",
 				empty
 			| "alpine" + .),
 			if .arches | has("windows-amd64") and .["windows-amd64"].url then