Generate manifests in `flux-{go,scm}` AUR packages

This commit makes a couple of changes to the `flux-{go,scm}` packages
so that they properly build again:

- The manifests are generated before the compilation of the `flux`
  binary.
- The `makedepends` have been updated to require a version of Go
  `>=1.16` (which is a requirement for `embed`).
- The `makedepends` have been updated to require a `kustomize` version
  `>=3.0` (as we use `transformers`).

Signed-off-by: Hidde Beydals <hello@hidde.co>

.github/aur/flux-go/PKGBUILD.template

@@ -12,7 +12,7 @@ provides=("flux-bin")
 conflicts=("flux-bin")
 replaces=("flux-cli")
 depends=("glibc")
-makedepends=("go")
+makedepends=('go>=1.16', 'kustomize>=3.0')
 optdepends=('kubectl: for apply actions on the Kubernetes cluster',
 'bash-completion: auto-completion for flux in Bash',
 'zsh-completions: auto-completion for flux in ZSH')
@@ -30,8 +30,9 @@ build() {
   export CGO_CFLAGS="$CFLAGS"
   export CGO_CXXFLAGS="$CXXFLAGS"
   export CGO_CPPFLAGS="$CPPFLAGS"
-  export GOFLAGS="-buildmode=pie -trimpath -ldflags=-linkmode=external -mod=readonly -modcacherw"
-  go build -ldflags "-X main.VERSION=${pkgver}" -o ${_srcname} ./cmd/flux
+  export GOFLAGS="-buildmode=pie -trimpath -mod=readonly -modcacherw"
+  ./manifests/scripts/bundle.sh "${PWD}/manifests" "${PWD}/cmd/flux/manifests"
+  go build -ldflags "-linkmode=external -X main.VERSION=${pkgver}" -o ${_srcname} ./cmd/flux
 }
 
 check() {

.github/aur/flux-scm/PKGBUILD.template

@@ -11,7 +11,7 @@ license=("APACHE")
 provides=("flux-bin")
 conflicts=("flux-bin")
 depends=("glibc")
-makedepends=("go")
+makedepends=('go>=1.16', 'kustomize>=3.0')
 optdepends=('kubectl: for apply actions on the Kubernetes cluster',
 'bash-completion: auto-completion for flux in Bash',
 'zsh-completions: auto-completion for flux in ZSH')
@@ -32,8 +32,9 @@ build() {
   export CGO_CFLAGS="$CFLAGS"
   export CGO_CXXFLAGS="$CXXFLAGS"
   export CGO_CPPFLAGS="$CPPFLAGS"
-  export GOFLAGS="-buildmode=pie -trimpath -ldflags=-linkmode=external -mod=readonly -modcacherw"
-  go build -ldflags "-X main.VERSION=${pkgver}" -o ${_srcname} ./cmd/flux
+  export GOFLAGS="-buildmode=pie -trimpath -mod=readonly -modcacherw"
+  make cmd/flux/manifests
+  go build -ldflags "-linkmode=external -X main.VERSION=${pkgver}" -o ${_srcname} ./cmd/flux
 }
 
 check() {