Traing to run the 'example' folder

[srlopez]

I'm trying to raise the example in the example directory. Currently working on Linux Ubuntu 20.04.
I don't know if this is the problem, I have updated flutter sdk to 1.26 to have dart verison >=2.12.
Still I get the following error:

The current Dart SDK version is 2.12.0-259.16.beta.

Because camera_with_rtmp_example requires SDK version >=2.12.0 <3.0.0, version solving failed.
pub get failed (1; Because camera_with_rtmp_example requires SDK version >=2.12.0 <3.0.0, version solving failed.)

My flutter doctor -v

[✓] Flutter (Channel beta, 1.26.0-17.8.pre, on Linux, locale en_US.UTF-8)
    • Flutter version 1.26.0-17.8.pre at /home/santi/sdk/flutter1.26
    • Framework revision 044f2cf560 (1 year, 1 month ago), 2021-02-24 13:02:05
      -0800
    • Engine revision 042c82b02c
    • Dart version 2.12.0 (build 2.12.0-259.16.beta)

[✓] Android toolchain - develop for Android devices (Android SDK version
    32.1.0-rc1)
    • Android SDK at /home/santi/sdk/android
    • Platform android-32, build-tools 32.1.0-rc1
    • Java binary at: /home/santi/sdk/studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Android Studio
    • Android Studio at /home/santi/sdk/studio
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • android-studio-dir = /home/santi/sdk/studio
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)

[✓] Connected device (1 available)
    • Android SDK built for x86 (mobile) • emulator-5554 • android-x86 • Android
      11 (API 30) (emulator)

• No issues found!

Shows the correct version of dart.
Please help!

¿Which is the best enviroment to setup the example?
Thanks