migrate backward-cpp to conan v2

[AndreyMlashkin]

This PR was auto-generated by a bash script. Most of the recipes (around 80%) can be built. It this one is failing, feel free to contribute a manual fix.

• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the conan-center hook activated.

[conan-center-bot]

Failure in build 1 (0d5646fe6080934177c80ffc53476a332c1901eb):

• backward-cpp/1.5@:
  Error running command conan info backward-cpp/1.5@#384b509bb4aaf42177e3bf97b4b47d10 --json {jsonName} -pr {profileName}:

  [settings]
  arch=x86_64
  build_type=Release
  compiler=apple-clang
  compiler.libcxx=libc++
  compiler.version=11.0
  os=Macos
  [options]
  backward-cpp:shared=False
  
  ...
  ERROR: backward-cpp/1.5: Error in validate() method, line 82
  	if self.settings.os not in self._supported_os:
  while calling '_supported_os', line 45
  	if tools.scm.Version(self.version) >= "1.5":
  	AttributeError: module 'conan.tools' has no attribute 'scm'
  

• backward-cpp/1.4@:
  Error running command conan info backward-cpp/1.4@#3da6a77ce4f7f807fa8472104f4caef4 --json {jsonName} -pr {profileName}:

  [settings]
  arch=x86_64
  build_type=Release
  compiler=apple-clang
  compiler.libcxx=libc++
  compiler.version=11.0
  os=Macos
  [options]
  backward-cpp:shared=False
  
  ...
  ERROR: backward-cpp/1.4: Error in validate() method, line 82
  	if self.settings.os not in self._supported_os:
  while calling '_supported_os', line 45
  	if tools.scm.Version(self.version) >= "1.5":
  	AttributeError: module 'conan.tools' has no attribute 'scm'
  

• backward-cpp/1.6@:
  Error running command conan info backward-cpp/1.6@#340422a7e88324bb82dcb45fba2aea23 --json {jsonName} -pr {profileName}:

  [settings]
  arch=x86_64
  build_type=Release
  compiler=apple-clang
  compiler.libcxx=libc++
  compiler.version=11.0
  os=Macos
  [options]
  backward-cpp:shared=False
  
  ...
  ERROR: backward-cpp/1.6: Error in validate() method, line 82
  	if self.settings.os not in self._supported_os:
  while calling '_supported_os', line 45
  	if tools.scm.Version(self.version) >= "1.5":
  	AttributeError: module 'conan.tools' has no attribute 'scm'
  

---

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