Avoid rpminspect "specname" failures in gating

The spec filename (dwz.spec) does not exactly match the name of the
package (gcc-toolset-14-dwz) which with the default rpminspect
configuration leads to:

  The spec file name does not match the expected NAME.spec
  format. Rename the spec file to conform to this policy.

Let's add a piece of configuration for rpminspect that would accept
the difference.

rpminspect.yaml

@@ -0,0 +1,10 @@
+runpath:
+  allowed_paths:
+    - /usr/lib64
+
+specname:
+    # In GCC toolsets builds, the spec file name and the package are not
+    # exactly the same, the package is prefixed with gcc-toolset-NN-.
+    # Let's ignore the prefix in the specname test.
+    match: suffix
+    primary: filename