Update regression test expected value and pin deps

Signed-off-by: Dan Luhring <dan.luhring@anchore.com>

test/integration/regression_test.go

@@ -24,7 +24,7 @@ func TestRegression212ApkBufferSize(t *testing.T) {
 		t.Fatalf("failed to catalog image: %+v", err)
 	}
 
-	expectedPkgs := 57
+	expectedPkgs := 58
 	actualPkgs := 0
 	for range catalog.Enumerate(pkg.ApkPkg) {
 		actualPkgs += 1

test/integration/test-fixtures/image-large-apk-data/Dockerfile

@@ -1,2 +1,5 @@
-FROM alpine:latest
-RUN apk add tzdata vim alpine-sdk
+FROM alpine@sha256:d9a7354e3845ea8466bb00b22224d9116b183e594527fb5b6c3d30bc01a20378
+RUN apk add --no-cache \
+            tzdata=2020f-r0 \
+            vim=8.2.2320-r0 \
+            alpine-sdk=1.0-r0