adding runkit to developer docker image

[brettmc]

runkit7 is used by AWS instrumentation over in -contrib
in passing, bump ast to latest stable version

[codecov]

Codecov Report

Merging #800 (9e7857e) into main (4dd375f) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main     #800      +/-   ##
============================================
- Coverage     80.40%   80.37%   -0.03%     
- Complexity     1765     1766       +1     
============================================
  Files           222      222              
  Lines          4516     4520       +4     
============================================
+ Hits           3631     3633       +2     
- Misses          885      887       +2     

Flag	Coverage Δ
7.4	80.37% <ø> (-0.03%)	⬇️
8.0	80.40% <ø> (-0.03%)	⬇️
8.1	80.40% <ø> (-0.03%)	⬇️

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Impacted Files	Coverage Δ
...PI/Common/Instrumentation/InstrumentationTrait.php	94.73% <0.00%> (-5.27%)	⬇️

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