Perform regexp compile at package level

Author: cmaglie

arduino/cores/packagemanager/loader.go

@@ -420,6 +420,8 @@ func convertLegacyPlatformToPluggableDiscovery(platform *cores.PlatformRelease)
 	}
 }
 
+var netPropRegexp = regexp.MustCompile(`\{upload\.network\.([^}]+)\}`)
+
 func convertLegacyNetworkPatternToPluggableDiscovery(props *properties.Map, newToolName string) *properties.Map {
 	pattern, ok := props.GetOk("upload.network_pattern")
 	if !ok {
@@ -434,7 +436,6 @@ func convertLegacyNetworkPatternToPluggableDiscovery(props *properties.Map, newT
 		pattern = strings.ReplaceAll(pattern, "{network.password}", "{upload.field.password}")
 	}
 	// Search for "{upload.network.PROPERTY}"" and convert it to "{upload.port.property.PROPERTY}"
-	netPropRegexp := regexp.MustCompile(`\{upload\.network\.([^}]+)\}`)
 	for netPropRegexp.MatchString(pattern) {
 		netProp := netPropRegexp.FindStringSubmatch(pattern)[1]
 		pattern = strings.ReplaceAll(pattern, "{upload.network."+netProp+"}", "{upload.port.properties."+netProp+"}")