Add French edition (#18)

* Add French edition

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: giswqs

README.md

@@ -21,6 +21,8 @@ Welcome to the official repository for **_Spatial Data Management with DuckDB: F
 
 - 🇨🇳 **Chinese PDF Edition (412 pages):** 中文电子版可在 Leanpub 购买 ([link](https://leanpub.com/duckdb-zh))
 
+- 🇫🇷 **French PDF Edition (474 pages):** Edition en français disponible en Leanpub ([link](https://leanpub.com/duckdb-fr))
+
 ## Cite the Book
 
 If you use this book in your research or teaching, please consider citing it as follows:

index.md

@@ -21,6 +21,8 @@ Welcome to the official website for **_Spatial Data Management with DuckDB: From
 
 - 🇨🇳 **Chinese PDF Edition (412 pages):** 中文电子版可在 Leanpub 购买 ([link](https://leanpub.com/duckdb-zh))
 
+- 🇫🇷 **French PDF Edition (474 pages):** Edition en français disponible en Leanpub ([link](https://leanpub.com/duckdb-fr))
+
 ## Cite the Book
 
 If you use this book in your research or teaching, please consider citing it as follows: