Remove last years api deprecations

[arturbosch]

No description provided.

[codecov]

Codecov Report

Merging #3035 into master will increase coverage by 0.13%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #3035      +/-   ##
============================================
+ Coverage     79.17%   79.30%   +0.13%     
- Complexity     2545     2556      +11     
============================================
  Files           434      432       -2     
  Lines          7731     7718      -13     
  Branches       1468     1467       -1     
============================================
  Hits           6121     6121              
+ Misses          824      811      -13     
  Partials        786      786              

Impacted Files	Coverage Δ	Complexity Δ
...n/kotlin/io/gitlab/arturbosch/detekt/api/Config.kt	100.00% <ø> (ø)	0.00 <0.00> (ø)
.../kotlin/io/gitlab/arturbosch/detekt/api/Context.kt	58.33% <ø> (+14.58%)	0.00 <0.00> (ø)
...ain/kotlin/io/gitlab/arturbosch/detekt/api/Rule.kt	93.33% <ø> (ø)	13.00 <0.00> (ø)
...in/io/gitlab/arturbosch/detekt/api/SplitPattern.kt	92.30% <ø> (+3.41%)	19.00 <0.00> (ø)
.../gitlab/arturbosch/detekt/api/internal/BaseRule.kt	100.00% <ø> (ø)	6.00 <0.00> (ø)

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[schalkms]

Feels good to remove this.