Update EmittanceInvariants.cpp

Update default cubic roots alg.

src/particles/diagnostics/EmittanceInvariants.cpp

@@ -125,7 +125,7 @@ namespace impactx::diagnostics
         // Caution: The order of e1,e2,e3 should be consistent with the
         // order ex,ey,et in the limit of uncoupled transport.
         // The order below is important and has been checked.
-        roots = CubicRootsAlg(a,b,c,d);
+        roots = CubicRootsTrig(a,b,c,d);
         amrex::ParticleReal e1 = sqrt(std::get<1>(roots));
         amrex::ParticleReal e2 = sqrt(std::get<2>(roots));
         amrex::ParticleReal e3 = sqrt(std::get<0>(roots));