#132 docs: update version references in README.md (#133)

Update package version from 0.2.12 to 0.2.15 to match Cargo.toml.

Author: RAprogramm

README.md

@@ -107,7 +107,7 @@ The top section represents the entire project. Proceeding with folders and final
 The macros are available with the `macros` feature. Enable it in your `Cargo.toml`:
 
 ```toml
-telegram-webapp-sdk = { version = "0.2.12", features = ["macros"] }
+telegram-webapp-sdk = { version = "0.2.15", features = ["macros"] }
 ```
 
 Reduce boilerplate in Telegram Mini Apps using the provided macros:
@@ -171,7 +171,7 @@ telegram-webapp-sdk = "0.2"
 Enable optional features as needed:
 
 ```toml
-telegram-webapp-sdk = { version = "0.2.12", features = ["macros", "yew", "mock"] }
+telegram-webapp-sdk = { version = "0.2.15", features = ["macros", "yew", "mock"] }
 ```
 
 - `macros` — enables `telegram_app!`, `telegram_page!`, and `telegram_router!`.