feat: allow "any" to specify a "binary" with no arch/os deps (#7230)

cosmovisor/README.md

@@ -122,6 +122,7 @@ as JSON under the `"binaries"` key, eg:
   }
 }
 ```
+The `"any"` key, if it exists, will be used as a default if there is not a specific os/architecture key.
 2. Store a link to a file that contains all information in the above format (eg. if you want
 to specify lots of binaries, changelog info, etc without filling up the blockchain).
 

cosmovisor/upgrade.go

@@ -121,7 +121,10 @@ func GetDownloadURL(info *UpgradeInfo) (string, error) {
 	if err := json.Unmarshal([]byte(doc), &config); err == nil {
 		url, ok := config.Binaries[osArch()]
 		if !ok {
-			return "", fmt.Errorf("cannot find binary for os/arch: %s", osArch())
+			url, ok = config.Binaries["any"]
+		}
+		if !ok {
+			return "", fmt.Errorf("cannot find binary for os/arch: neither %s, nor any", osArch())
 		}
 
 		return url, nil

cosmovisor/upgrade_test.go

@@ -159,6 +159,14 @@ func TestGetDownloadURL(t *testing.T) {
 			info: `{"binaries": {"linux/amd64": "https://foo.bar/", "windows/amd64": "https://something.else"}}`,
 			url:  "https://foo.bar/",
 		},
+		"any architecture not used": {
+			info: `{"binaries": {"linux/amd64": "https://foo.bar/", "*": "https://something.else"}}`,
+			url:  "https://foo.bar/",
+		},
+		"any architecture used": {
+			info: `{"binaries": {"linux/arm": "https://foo.bar/arm-only", "any": "https://foo.bar/portable"}}`,
+			url:  "https://foo.bar/portable",
+		},
 		"missing binary": {
 			info:  `{"binaries": {"linux/arm": "https://foo.bar/"}}`,
 			isErr: true,