Change user output with term `upsert` to `insert or update`

[johannes-b]

Describe the bug
While the term upsert is very technical, it may cause confusion when used in output messages. For example:

2023/04/28 14:08:01 INFO  Projects to be deployed:
2023/04/28 14:08:01 INFO    - srg-config-as-code
2023/04/28 14:08:01 INFO  Environments to deploy to:
2023/04/28 14:08:01 INFO    - pvy27067
2023/04/28 14:08:01 INFO  Deploying configurations to environment `pvy27067`...
2023/04/28 14:08:01 INFO        Deploying config srg-config-as-code:app:dynatrace.site.reliability.guardian:guardians:srg
2023/04/28 14:08:02 WARN  Failed to upsert config "srg". Waiting for 5s before retrying...
2023/04/28 14:08:07 WARN  Failed to upsert config "srg". Waiting for 5s before retrying...
2023/04/28 14:08:12 WARN  Failed to upsert config "srg". Waiting for 5s before retrying...

Note: Definition of term:

The term upsert is a portmanteau – a combination of the words “update” and “insert.” In the context of relational databases, an upsert is a database operation that will update an existing row if a specified value already exists in a table, and insert a new row if the specified value doesn't already exist.

Expected behavior
Please change the output messages from upsert to insert or update.

Additional context
Add any other context about the problem here.

[UnseenWizzard]

wording changed as of 2.0.3