Build on Ubuntu 20.04

Signed-off-by: itowlson <ivan.towlson@fermyon.com>

Author: itowlson

.github/workflows/release.yaml

@@ -52,7 +52,7 @@ jobs:
       matrix:
         config:
           - {
-              os: "ubuntu-latest",
+              os: "ubuntu-20.04",
               arch: "amd64",
               wasiSDK: "linux",
               extension: "",
@@ -61,7 +61,7 @@ jobs:
               targetDir: "target/release",
             }
           - {
-              os: "ubuntu-latest",
+              os: "ubuntu-20.04",
               arch: "aarch64",
               wasiSDK: "linux",
               extension: "",