fix: add missing deviation timestamps

[mfiedorowicz]

This pull request includes changes to the diode-server repository, specifically focusing on adding timestamp fields to deviation records and updating test cases accordingly. The most important changes include adding IngestionTs and LastUpdateTs fields to the deviation records and modifying test cases to validate these new fields.

Enhancements to Deviation Records:

• Added IngestionTs and LastUpdateTs fields to the deviation records in the RetrieveDeviations and RetrieveDeviationByID methods in diode-server/dbstore/postgres/repository.go. [1] [2]

Updates to Test Cases:

• Included time and github.com/stretchr/testify/assert imports in diode-server/reconciler/deviation_test.go.
• Added IngestionTs and LastUpdateTs values to test deviation records in TestRetrieveDeviations and TestRetrieveDeviationByID functions. [1] [2] [3] [4]
• Updated assertions in test cases to include checks for the new IngestionTs and LastUpdateTs fields. [1] [2]

[github-actions]

Go test coverage

STATUS	ELAPSED	PACKAGE	COVER	PASS	FAIL	SKIP
🟢 PASS	0.00s	github.com/netboxlabs/diode/diode-server/dbstore/postgres	0.0%	0	0	0
🟢 PASS	1.25s	github.com/netboxlabs/diode/diode-server/ingester	75.4%	9	0	0
🟢 PASS	1.06s	github.com/netboxlabs/diode/diode-server/migrator	70.4%	4	0	0
🟢 PASS	0.01s	github.com/netboxlabs/diode/diode-server/netbox	0.0%	0	0	0
🟢 PASS	1.76s	github.com/netboxlabs/diode/diode-server/netboxdiodeplugin	78.9%	42	0	0
🟢 PASS	1.43s	github.com/netboxlabs/diode/diode-server/reconciler	76.5%	41	0	0
🟢 PASS	1.09s	github.com/netboxlabs/diode/diode-server/reconciler/applier	81.8%	1	0	0
🟢 PASS	0.00s	github.com/netboxlabs/diode/diode-server/reconciler/changeset	0.0%	0	0	0
🟢 PASS	1.32s	github.com/netboxlabs/diode/diode-server/reconciler/differ	82.5%	92	0	0
🟢 PASS	1.02s	github.com/netboxlabs/diode/diode-server/server	85.7%	14	0	0
🟢 PASS	1.01s	github.com/netboxlabs/diode/diode-server/version	100.0%	1	0	0

Total coverage: 74.0%