Use stable Buildkit syntax

We no longer need to be on an experimental branch - all the
Dockerfile features we need were released on 1.3.

commit-id:b083856a

Dockerfile.lint

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 FROM docker.io/golang:1.17.5@sha256:90d1ab81f3d157ca649a9ff8d251691b810d95ea6023a03cdca139df58bca599
 
 RUN useradd -u 1000 -U -m -d /home/lint lint

Dockerfile.proto

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 FROM docker.io/golang:1.17.5@sha256:90d1ab81f3d157ca649a9ff8d251691b810d95ea6023a03cdca139df58bca599 AS go-tools
 
 RUN mkdir /app
@@ -9,7 +9,7 @@ ADD tools/go.* /app/tools/
 RUN --mount=type=cache,target=/root/.cache --mount=type=cache,target=/go \
 	cd /app/tools && CGO_ENABLED=0 ./build.sh
 
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 FROM docker.io/golang:1.17.5@sha256:90d1ab81f3d157ca649a9ff8d251691b810d95ea6023a03cdca139df58bca599 AS go-build
 
 COPY --from=go-tools /app /app

bridge_ui/Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 
 # Derivative of ethereum/Dockerfile, look there for an explanation on how it works.
 FROM node:16-alpine@sha256:004dbac84fed48e20f9888a23e32fa7cf83c2995e174a78d41d9a9dd1e051a20

ethereum/Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 FROM node:lts-alpine@sha256:2ae9624a39ce437e7f58931a5747fdc60224c6e40f8980db90728de58e22af7c
 
 # npm wants to clone random Git repositories - lovely.

event_database/cloud_functions/Dockerfile.run

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 FROM gcr.io/buildpacks/gcp/run@sha256:04f2e841ebbcc140c9f817e274caf8ae8ae0341008c4e01d8ef84cb8aa8c312a
 
 # the "builtby=tilt" label is how Tilt determines which containters can be purged.

explorer/Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 
 # Derivative of ethereum/Dockerfile, look there for an explanation on how it works.
 FROM node:16-alpine@sha256:004dbac84fed48e20f9888a23e32fa7cf83c2995e174a78d41d9a9dd1e051a20

node/Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 FROM docker.io/golang:1.17.5@sha256:90d1ab81f3d157ca649a9ff8d251691b810d95ea6023a03cdca139df58bca599
 
 WORKDIR /app

solana/Dockerfile.wasm

@@ -1,4 +1,4 @@
-# syntax=docker.io/docker/dockerfile:experimental@sha256:de85b2f3a3e8a2f7fe48e8e84a65f6fdd5cd5183afa6412fff9caa6871649c44
+# syntax=docker.io/docker/dockerfile:1.3@sha256:42399d4635eddd7a9b8a24be879d2f9a930d0ed040a61324cfdf59ef1357b3b2
 FROM docker.io/library/rust:1.49@sha256:a50165ea96983c21832578afb1c8c028674c965bc1ed43b607871b1f362e06a5 AS build
 
 RUN apt-get update && apt-get install -y libssl-dev libudev-dev pkg-config zlib1g-dev llvm clang