Bump min frontend of fetchzip due to vibe.d incompatibility for the ...

testregistry

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Opening file /tmp/gitcompatibledubpackage-cb607641-d990-4f5c-a426-0e158a14689e.zip
rawRead must take a non-empty buffer
Full exception: object.Exception@/home/travis/dlang/dmd-2.075.1/linux/bin64/../../src/phobos/std/stdio.d(902): rawRead must take a non-empty buffer
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/home/travis/dlang/dmd-2.075.1/linux/bin64/../../src/phobos/std/stdio.d:902 @safe ubyte[] std.stdio.File.rawRead!(ubyte).rawRead(ubyte[]) [0xa16c4b]
source/dub/internal/vibecompat/core/file.d:46 @trusted void dub.internal.vibecompat.core.file.RangeFile.rawRead(ubyte[]) [0xa01908]
source/dub/internal/vibecompat/core/file.d:42 @safe ubyte[] dub.internal.vibecompat.core.file.RangeFile.readAll() [0xa01882]
source/dub/packagemanager.d:360 dub.package_.Package
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Don't break out of the retry loop for ZipExceptions - fixes #1336