readme: use log.Panic instead of panic for example

Author: markus-wa

README.md

@@ -85,6 +85,7 @@ package main
 
 import (
 	"fmt"
+    "log"
 	"os"
 
 	dem "github.com/markus-wa/demoinfocs-golang/v2/pkg/demoinfocs"
@@ -94,7 +95,7 @@ import (
 func main() {
 	f, err := os.Open("/path/to/demo.dem")
 	if err != nil {
-		panic(err)
+		log.Panic("failed to open demo file: ", err)
 	}
 	defer f.Close()
 
@@ -117,7 +118,7 @@ func main() {
 	// Parse to end
 	err = p.ParseToEnd()
 	if err != nil {
-		panic(err)
+		log.Panic("failed to parse demo: ", err)
 	}
 }
 ```

pkg/demoinfocs/examples_test.go

@@ -2,6 +2,7 @@ package demoinfocs_test
 
 import (
 	"fmt"
+	"log"
 	"os"
 	"testing"
 
@@ -14,9 +15,9 @@ This will print all kills of a demo in the format '[[killer]] <[[weapon]] [(HS)]
 */
 //noinspection GoUnhandledErrorResult
 func ExampleParser() {
-	f, err := os.Open("../../test/cs-demos/default.dem")
+	f, err := os.Open("../../test/cs-demos/default.demx")
 	if err != nil {
-		panic(err)
+		log.Panic("failed to open demo file: ", err)
 	}
 
 	defer f.Close()
@@ -42,7 +43,7 @@ func ExampleParser() {
 	// Parse to end
 	err = p.ParseToEnd()
 	if err != nil {
-		panic(err)
+		log.Panic("failed to parse demo: ", err)
 	}
 }