Dynatrace Exporter uses "cumulative" temporality by default

[Anika-Sol]

Currently metrics exported to Dynatrace have the default temporality cumulative.
According to the Dynatrace documentation cumulative is not yet supported and delta should be used.

The default temporality leads to metrics not being accepted by Dynatrace.

[KarstenSchnitter]

Thanks for reporting this issue. A fix is available with #174.

[KarstenSchnitter]

Fix is merged and will be provided with version 3.8.3. This release should be available on Maven Central soon.