Rename Job & Count UUID to Partition ID

Renames the uuid and job_uuid fields to partition ID. This is the more
correct name as this value is not a true UUID, is in-fact a partition
ID, and doesn't need to be globally unique.

```shell
$ grep -nir . -e "uuid"
./go.sum:98:github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
./go.sum:167:github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
$
```

Signed-off-by: joshvanl <me@joshvanl.dev>

README.md

@@ -84,7 +84,7 @@ Leadership keys are associated with an ETCD lease of 20s TTL to prevent stale le
 ## Counter
 
 An associated `counters` key is used to track the current state of a job that is scheduled.
-It includes the last trigger time (if triggered), the number of times the job has been triggered, and the UUID of the associated job with the same name.
+It includes the last trigger time (if triggered), the number of times the job has been triggered, and the Partition ID of the associated job with the same name.
 Counters are lazily deleted in bulk by a garbage collector that runs every 180s in an effort to reduce pressure of jobs triggering.
 
 The scheduler will never miss triggering jobs.

cron_test.go

@@ -447,7 +447,7 @@ func Test_schedule(t *testing.T) {
 			Begin: &api.JobStored_DueTime{
 				DueTime: timestamppb.New(now),
 			},
-			Uuid: 123,
+			PartitionId: 123,
 			Job: &api.Job{
 				DueTime: ptr.Of(now.Format(time.RFC3339)),
 			},
@@ -518,15 +518,15 @@ func Test_schedule(t *testing.T) {
 			Begin: &api.JobStored_DueTime{
 				DueTime: timestamppb.New(now),
 			},
-			Uuid: 123,
+			PartitionId: 123,
 			Job: &api.Job{
 				DueTime: ptr.Of(now.Format(time.RFC3339)),
 			},
 		}
 		counter := &api.Counter{
-			LastTrigger: nil,
-			Count:       0,
-			JobUuid:     123,
+			LastTrigger:    nil,
+			Count:          0,
+			JobPartitionId: 123,
 		}
 
 		jobBytes, err := proto.Marshal(job)
@@ -599,15 +599,15 @@ func Test_schedule(t *testing.T) {
 			Begin: &api.JobStored_DueTime{
 				DueTime: timestamppb.New(now),
 			},
-			Uuid: 123,
+			PartitionId: 123,
 			Job: &api.Job{
 				DueTime: ptr.Of(now.Format(time.RFC3339)),
 			},
 		}
 		counter := &api.Counter{
-			LastTrigger: timestamppb.New(now),
-			Count:       1,
-			JobUuid:     123,
+			LastTrigger:    timestamppb.New(now),
+			Count:          1,
+			JobPartitionId: 123,
 		}
 
 		jobBytes, err := proto.Marshal(job)

internal/counter/counter.go

@@ -83,7 +83,7 @@ func New(ctx context.Context, opts Options) (*Counter, bool, error) {
 			client:     opts.Client,
 			schedule:   opts.Schedule,
 			job:        opts.Job,
-			count:      &api.Counter{JobUuid: opts.Job.GetUuid()},
+			count:      &api.Counter{JobPartitionId: opts.Job.GetPartitionId()},
 			yard:       opts.Yard,
 			collector:  opts.Collector,
 			triggerRequest: &api.TriggerRequest{
@@ -105,10 +105,10 @@ func New(ctx context.Context, opts Options) (*Counter, bool, error) {
 		return nil, false, err
 	}
 
-	// If the job UUID is the same, recover the counter state, else we start
-	// again.
-	if count.GetJobUuid() != opts.Job.GetUuid() {
-		count = &api.Counter{JobUuid: opts.Job.GetUuid()}
+	// If the job partition ID is the same, recover the counter state, else we
+	// start again.
+	if count.GetJobPartitionId() != opts.Job.GetPartitionId() {
+		count = &api.Counter{JobPartitionId: opts.Job.GetPartitionId()}
 		b, err := proto.Marshal(count)
 		if err != nil {
 			return nil, false, err