py-numpy: conflict with gcc11 and switch master to main (#24573)

Fix syntax of conflict between numpy 1.21.0 and gcc11 to that the clingo
concretizer recognizes it.
In addition the upstream master branch was renamed to main.

var/spack/repos/builtin/packages/py-numpy/package.py

@@ -3,10 +3,11 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
-from spack import *
 import platform
 import subprocess
 
+from spack import *
+
 
 class PyNumpy(PythonPackage):
     """NumPy is the fundamental package for scientific computing with Python.
@@ -21,7 +22,8 @@ class PyNumpy(PythonPackage):
 
     maintainers = ['adamjstewart']
 
-    version('master', branch='master')
+    version('main', branch='main')
+    version('master', branch='main', deprecated=True)
     version('1.21.0', sha256='e80fe25cba41c124d04c662f33f6364909b985f2eb5998aaa5ae4b9587242cce')
     version('1.20.3', sha256='e55185e51b18d788e49fe8305fd73ef4470596b33fc2c1ceb304566b99c71a69')
     version('1.20.2', sha256='878922bf5ad7550aa044aa9301d417e2d3ae50f0f577de92051d739ac6096cee')
@@ -115,8 +117,9 @@ class PyNumpy(PythonPackage):
     patch('check_executables4.patch', when='@1.14.0:1.15.4')
     patch('check_executables5.patch', when='@:1.13.3')
 
-    # https://github.com/numpy/numpy/releases/tag/v1.21.0
-    conflicts('%gcc@11.1', when='@1.21.0')
+    # version 1.21.0 runs into an infinit loop during printing
+    # (e.g. print(numpy.ones(1000)) when compiled with gcc 11
+    conflicts('%gcc@11:', when='@1.21.0')
 
     # GCC 4.8 is the minimum version that works
     conflicts('%gcc@:4.7', msg='GCC 4.8+ required')
@@ -150,6 +153,7 @@ def flag_handler(self, name, flags):
                                    '{0}'.format(gcc_version))
             if gcc_version <= Version('5.1'):
                 flags.append(self.compiler.c99_flag)
+
         return (flags, None, None)
 
     @run_before('build')