Fix link to CurliPie tool (httpie#1582)

* Fix link to CurliPie tool

* Use the link to web version for CurliPie

Co-authored-by: Jan Brasna <1784648+janbrasna@users.noreply.github.com>

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Co-authored-by: Jan Brasna <1784648+janbrasna@users.noreply.github.com>

Author: hongquan

docs/README.md

@@ -2568,7 +2568,7 @@ HTTPie plays exceptionally well with the following tools:
 
 Helpers to convert from other client tools:
 
-- [CurliPie](https://curlipie.now.sh/) help convert cURL command line to HTTPie command line
+- [CurliPie](https://curlipie.open-api.vn) — library to convert cURL commands to HTTPie
 
 #### Alternatives