add hep tags to some newly added hep packages (#21653)

var/spack/repos/builtin/packages/apfel/package.py

@@ -15,6 +15,8 @@ class Apfel(AutotoolsPackage):
     homepage = "https://github.com/scarrazza/apfel"
     url      = "https://github.com/scarrazza/apfel/archive/3.0.4.tar.gz"
 
+    tags = ['hep']
+
     version('3.0.4', sha256='c7bfae7fe2dc0185981850f2fe6ae4842749339d064c25bf525b4ef412bbb224')
 
     depends_on('swig', when='+python')

var/spack/repos/builtin/packages/unigen/package.py

@@ -18,6 +18,8 @@ class Unigen(MakefilePackage):
     homepage = "https://www.gsi.de/work/wissenschaftliche_netzwerke/helmholtz_virtuelle_institute/unigen.htm"
     url      = "https://github.com/FairRootGroup/UniGen/archive/v2.3.tar.gz"
 
+    tags = ['hep']
+
     version('2.3', sha256='8783bcabbdf8c50dab6e93153cff9cfb267a9a9e61aef51bf1e17679ba42a717')
     patch('unigen-2.3.patch', level=0)