Request minimal base 4.15

This corresponds to support for the latest 3 GHC versions.

megaparsec-tests/megaparsec-tests.cabal

@@ -25,7 +25,7 @@ library
     default-language: Haskell2010
     build-depends:
         QuickCheck >=2.10 && <2.15,
-        base >=4.13 && <5.0,
+        base >=4.15 && <5.0,
         bytestring >=0.2 && <0.12,
         containers >=0.5 && <0.7,
         hspec >=2.0 && <3.0,
@@ -64,7 +64,7 @@ test-suite tests
     default-language:   Haskell2010
     build-depends:
         QuickCheck >=2.10 && <2.15,
-        base >=4.13 && <5.0,
+        base >=4.15 && <5.0,
         bytestring >=0.2 && <0.12,
         case-insensitive >=1.2 && <1.3,
         containers >=0.5 && <0.7,

megaparsec.cabal

@@ -56,7 +56,7 @@ library
 
     default-language: Haskell2010
     build-depends:
-        base >=4.13 && <5.0,
+        base >=4.15 && <5.0,
         bytestring >=0.2 && <0.12,
         case-insensitive >=1.2 && <1.3,
         containers >=0.5 && <0.7,
@@ -84,7 +84,7 @@ benchmark bench-speed
     hs-source-dirs:   bench/speed
     default-language: Haskell2010
     build-depends:
-        base >=4.13 && <5.0,
+        base >=4.15 && <5.0,
         bytestring >=0.2 && <0.12,
         containers >=0.5 && <0.7,
         criterion >=0.6.2.1 && <1.7,
@@ -104,7 +104,7 @@ benchmark bench-memory
     hs-source-dirs:   bench/memory
     default-language: Haskell2010
     build-depends:
-        base >=4.13 && <5.0,
+        base >=4.15 && <5.0,
         bytestring >=0.2 && <0.12,
         containers >=0.5 && <0.7,
         deepseq >=1.3 && <1.5,