[MNG-6841] update plexus-interpolation to 1.26

[KroArtem]

Main site says plexus-interpolation version is 1.25 but apparently it's 1.26

https://codehaus-plexus.github.io/plexus-interpolation/

The main change in 1.26 is a performance improvement: codehaus-plexus/plexus-interpolation#23

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[khmarbaise]

Let's wait for CI result https://builds.apache.org/view/M-R/view/Maven/job/maven-box/job/maven/job/MNG-6841/

[khmarbaise]

Merged to master. Thanks for your contribution.