rename package

currently the file and package are written without camel case. This causes errors when gomobile tries to generate the JNI for Android.

./bin/gomobile: javac -d /var/folders/11/llkc5bss1bsfb05hp598vv_m0000gn/T/gomobile-work-098949177/javac-output -source 1.7 -target 1.7 -bootclasspath /Users/cyberta/Library/Android/sdk/platforms/android-31/android.jar go/Seq.java go/Universe.java go/error.java pgpverify/Logger.java pgpverify/PgpVerifier.java pgpverify/Pgpverify.java shapeshifter/Logger.java shapeshifter/Shapeshifter.java failed: exit status 1
shapeshifter/Shapeshifter.java:10: error: class ShapeShifter is public, should be declared in a file named ShapeShifter.java
public final class ShapeShifter implements Seq.Proxy {
             ^
shapeshifter/Shapeshifter.java:11: error: cannot access Shapeshifter
        static { Shapeshifter.touch(); }
                 ^
  bad source file: ./shapeshifter/Shapeshifter.java
    file does not contain class shapeshifter.Shapeshifter
    Please remove or make sure it appears in the correct subdirectory of the sourcepath.
2 errors

Renaming the file to shapeShifter.go and the package declaration in shapeshifter go to package shapeShifter fixes it.