Switched to JSON format for timing analysis report
Switched to JSON format for timing analysis report

Signed-off-by: Maciej Kurc <572803cc6e8d7bb35033942e4b03254951a2e0d6@antmicro.com>

SymbiFlow/nextpnr,YosysHQ/nextpnr,YosysHQ/nextpnr,SymbiFlow/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr