readme: Document compatibility with NDK r25 and remove workaround mention (rust-mobile#354)

NDK r25 works just as well as r24, and is the current LTS.  There are no
other releases planned between it and r26 launching in 2023, and
scheduled to be the next NDK.

The mention of our workaround is irrelevant given that it's something we
deal with for the user in the background, and the feature has evolved
many times through multiple PRs.  This allows us to drop the beta notion
for r23 which is long deprecated by now.

Author: MarijnS95

README.md

@@ -19,7 +19,7 @@ See [`ndk-examples`](./ndk-examples) for examples using the NDK and the README f
 
 `android-ndk-rs` aims to support at least the `LTS` and `Rolling Release` branches of the NDK, as described on [their wiki](https://github.com/android/ndk/wiki#supported-downloads). Additionally the `Beta Release` might be supported to prepare for an upcoming release.
 
-As of writing (2021-07-24) the following NDKs are tested:
+As of writing (2022-10-10) the following NDKs are tested:
 
 Branch | Version | Status | Working
 -|-|:-:|:-:
@@ -28,10 +28,9 @@ r19 | 19.2.5345600 | _Deprecated_ | :heavy_check_mark:
 r20 | 20.1.5948944 | _Deprecated_ | :heavy_check_mark:
 r21 | 21.4.7075529 | _Deprecated_ | :heavy_check_mark:
 r22 | 22.1.7171670 | _Deprecated_ | :heavy_check_mark:
-r23 | beta 1/2 | _Deprecated_ | :heavy_check_mark:
-r23 | 23.0.7272597-beta3 | _Deprecated_ | :heavy_check_mark: Workaround in [#189](https://github.com/rust-windowing/android-ndk-rs/pull/189)
-r23 | 23.1.7779620 | LTS | :heavy_check_mark: Workaround in [#189](https://github.com/rust-windowing/android-ndk-rs/pull/189)
-r24 | 24.0.7856742-beta1 | Rolling Release | :heavy_check_mark: Workaround in [#189](https://github.com/rust-windowing/android-ndk-rs/pull/189)
+r23 | 23.1.7779620 | _Deprecated_ | :heavy_check_mark:
+r24 | 24.0.8215888 | _Deprecated_ | :heavy_check_mark:
+r25 | 25.1.8937393 | LTS | :heavy_check_mark:
 
 
 ## Quick start: `Hello World` crate on Android