go.mod: add module dependencies

This provides reproducible builds for commands like
'go install github.com/aclements/go-misc/greplogs@latest'.

go.mod

@@ -0,0 +1,25 @@
+module github.com/aclements/go-misc
+
+go 1.17
+
+require (
+	github.com/aclements/go-gg v0.0.0-20170323211221-abd1f791f5ee
+	github.com/aclements/go-moremath v0.0.0-20210112150236-f10218a38794
+	golang.org/x/build v0.0.0-20210804225706-d1bc548deb19
+	golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97
+	golang.org/x/image v0.0.0-20210628002857-a66eb6448b8d
+	golang.org/x/tools v0.1.5
+)
+
+require (
+	github.com/ajstarks/svgo v0.0.0-20210406150507-75cfd577ce75 // indirect
+	github.com/gonum/blas v0.0.0-20181208220705-f22b278b28ac // indirect
+	github.com/gonum/floats v0.0.0-20181209220543-c233463c7e82 // indirect
+	github.com/gonum/internal v0.0.0-20181124074243-f884aa714029 // indirect
+	github.com/gonum/lapack v0.0.0-20181123203213-e4cdc5a0bff9 // indirect
+	github.com/gonum/matrix v0.0.0-20181209220409-c518dec07be9 // indirect
+	golang.org/x/mod v0.4.2 // indirect
+	golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c // indirect
+	golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+)