Keep OTel collector version updated in product telemetry functional test

[pleshakov]

https://github.com/nginxinc/nginx-gateway-fabric/pull/1659 added a functional test that install OTel collector in a cluster using helm. For predictability, the version of the chart is kept static in a go file:

const (
	. . .
	collectorChartVersion = "0.73.1"
)

Find a automated way to keep the version updated here similar to dependabot.

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[github-actions[bot]]

This issue was closed because it has been stalled for 14 days with no activity.

[bjee19]

#1832 Also adds a constant version which should be fixed to update automatically.

const (
    debugImage = "busybox:1.28"
)

[bjee19]

Update: #1832 no longer adds a constant version and thus does not need to be taken into consideration.